The most beautiful of all the zodiacal constellations is now visible, low toward the south-southeast as darkness falls. This is Scorpius the Scorpion. It really does look like a scorpion, one of the few star patterns that readily suggests the mythical form assigned to it by the ancients. Composed of several fairly bright stars, its body is formed by the upper stars of this star pattern; its tail slants toward the horizon, then curves to the left and upward, a fine stream of stars ending in a close pair of stars marking its stinger.

George Lovi (1939-1993), a well-known astronomy lecturer and author, used to say that it always bothered him that a striking star pattern such as Scorpius was made to represent
"...a lowly, creepy-crawly thing that has few friends."

In his book, The Stars in Our Heaven, author Peter Lum (1911-1983) provides a perspective like Mr. Lovi's:

"The scorpion . . . is an odd-shaped, insignificant creature, but its sting is out of proportion to its size and, although seldom fatal, is extremely painful; hence it is usually disliked, feared and avoided by anyone who has ever come in contact with him."

Just as Orion is the most striking winter stellar pattern, such a distinction can be claimed for Scorpius for the summer season. Interestingly, one legend has Scorpius representing the creature that stung Orion to death. To honor Orion, the Scorpion was placed opposite him in the sky, so that these celestial antagonists will never meet again. Indeed, when Orion disappears below the western horizon during spring evenings, the Scorpion is poking his head up in the southeast. In addition, they were commonly thought of in opposition to each other: Orion was the constellation of life, Scorpius that of death.

And yet, the whole figure of the scorpion is a magnificent sight — sort of a "celestial fishhook" — and is best appreciated now in a dark sky without any interference from bright moonlight. It really looks like a huge scorpion, with its long stinging tail curled over its back. Two closely spaced stars known as Shaula and Lesath mark the Scorpion's stinger. Astronomy popularizer Hans A. Rey (1898-1977) christened these stars the "Cat's Eyes," noting, "You will find the name quite fitting."

Best seen from southern locales

Scorpius is a constellation that can be best appreciated by southerners. Those who live in the far-northern United States, southern Canada or the British Isles will have part or even all of its tail hidden below the southern horizon. Thus, it is well worth seeking out a good, clear horizon to appreciate this majestic figure. As one progresses farther south, the Scorpion slowly climbs the southern sky. Those who live in Australia, New Zealand, South Africa, northern Argentina, Uruguay, most of Brazil, northern Chile, and southern Peru see Scorpius high overhead. The Milky Way passes through the lower extremities of the Scorpion. Here, clouds of stars and dark interstellar dust combine in a bewildering array as seen in binoculars and telescopes.

Ruddy contender to Mars

The Scorpion's brightest star is the first magnitude Antares, displaying a reddish hue. Antares appears due south at 10:30 p.m. local daylight time on Independence Day; a month later, you'll find it there two hours earlier as darkness falls. To the ancients, its distinctive red color suggested the planet Mars and the name Antares means literally "The Rival of Ares," Ares being the Greek name for the God of War. There was good reason for this, for unlike the fixed stars, the planets could wander against the starry background, and this ability to move had a magical, god-like quality.

Evidence of this lies in the very names of the planets, which represented ancient deities, and of the five bright planets, the one whose color appeared to come closest to that of blood was called Mars in honor of the god of war. But although often referred to as the "red planet," in the sky, it really appears more yellowish orange, fiery, or pumpkin-hued as opposed to red.

In contrast, Antares is one of the reddest stars in the sky. On those occasions when Mars passes just north of Antares, it is obvious which one is redder. So even when Mars is near opposition and appears to glow many times brighter, Antares still rivals it at least in color.

A star of many names

In the time of Confucius, the Chinese called this star Ta Who, "The Great Fire," at the heart of the Dragon of the East. Another Chinese legend refers to Antares and its two attendants — two fainter stars that flank it — as the Ming T'ang, the "Hall of Light" or the "Emperor's Council Hall." Those two stars are about equally bright — Sigma Scorpii (+2.8) and Tau Scorpii (+2.9). They are sometimes called the Praecordia — "the outworks of the heart," the heart of course being Antares.

The Romans called this mighty star Cor Scorpionis, meaning "heart of the scorpion," a title the French also use — Le Coeur de Scorpion. Some 5,000 years ago, the Persians thought of Antares as one of the four Royal Stars, a guardian of heaven.

Enormous celestial beacon

Antares is a cool, red supergiant star, about 550 light-years away. It is some 76,000 times more luminous and about 680 times the diameter of our sun. It's an irregular variable star, meaning that it expands and contracts in an unpredictable manner, causing its brightness to fluctuate. It has been observed to shine as brightly as magnitude +0.9, while at other times, its brightness has been down to +1.2. It usually ranks as the 15th on the list of the twenty-one brightest stars in the sky.

If our solar system were centered on Antares, the orbit of the Earth would easily fit within this star. Yet, despite these impressive statistics, it should be noted that the overall mass of Antares is only 13 to 16 times that of the sun, so it is not very dense. Its insides might be like a very hot vacuum.

Antares is also relatively cool as stars go, only about 6,100º F (3,400 ºC), compared to 11,000º F (6,000 ºC) for the sun. Its low temperature accounts for its ruddy color. It has a small, very hot companion, bluish white in color, yet has been described as appearing
as ". . . a little spark of glittering emerald" because of its proximity and contrast to ruddy Antares. The pair orbit each other over a span of nearly 900 years, separated by a distance of about 500 times Earth's distance from the sun.

Caught in the claws

Scorpions have two large claws in front, but this one seems to have had its claws clipped; they were cut off to form the constellation of Libra the Scales, one of the constellations of the zodiac and associated with Themis, the Greek goddess of justice, whose attribute was a pair of scales. These stars still both carry Arabic names: Zubeneschamali ("northern claw") and Zubenelgenubi ("southern claw"), to help distinguish them as originally belonging to Scorpius.

Lastly, it must be emphasized to those newcomers to astronomy that the currently accepted name of this constellation is Scorpius, not Scorpio. Principally, astrologers (and some older astronomy books) use the latter for labeling the zodiacal sign of that name.

Just stingin' the nomenclature.

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, Sky and Telescope, The Old Farmer's Almanac and other publications.

The May new moon arrives this weekend, ushering in several dark moonless nights perfect for exploring the majesty of our Milky Way, glimmering spring constellations and the ever-shifting procession of the planets.

May's new moon phase occurs at 4:01 p.m. EDT (2001 GMT) on May 16, as the moon passes close to the sun in the daytime sky.

The nights surrounding the new moon present beautifully dark skies for stargazers looking to navigate the sea of stars, nebulas and galaxies that haunt the post-sunset realm.

Visible planets

Turn your gaze west at sunset to spot Venus glowing as a bright "evening star" a little over 20 degrees above the horizon — roughly the width of two clenched fists held at arm's length against the night sky.

Jupiter glows another 20 degrees to the upper left of Venus, with Castor and Pollux, the brightest stars in the constellation Gemini, shining above. A pair of 10X50 binoculars will reveal a shoal of star-like objects surrounding the gas giant. These are Jupiter's largest natural satellites Io, Europa, Ganymede and Callisto, which are collectively known as the Galilean Moons in honor of their discoverer, the famed Italian astronomer Galileo Galilei.

Early birds are treated to an entirely different cast of planets as Saturn shines above the eastern horizon in the hour preceding dawn, with Mars rising to its lower left, chased by the golden light of the coming sun. Both Saturn and Mars will cling less than 20 degrees above the horizon at sunrise, so be sure to find a spot with a clear view to the east if you want to catch the planetary duo before they're lost in the glare of the sun.

Stars and constellations

May's new moon is a great time to spot a trio of celestial animals shining in the spring sky. Our first target is the great lion represented in the constellation Leo, whose mane and chest are represented by a sickle-like formation of stars that shines above the southwestern horizon after sunset in May, with Regulus at its lowest point.

The second-century Greek philosopher Ptolemy catalogued the constellation almost 2,000 years ago, seeing in it the Nemean Lion from the mythological tale of Heracles, which the hero was burdened with slaying as the first of his 12 labors.

Next, look 10 degrees above Leo's sickle head to find the faint stars of the constellation Leo Minor, the "little lion". This constellation was created by the Polish astronomer Johannes Hevelius in the year 1690. As a result, there are no great mythological tales of its origin, though it remains a pretty feature between the greater stellar citadels of Leo and Ursa Major.

To the lower right of Leo Minor is the magnitude +3.25 star Alpha Lyncis, which forms the leftmost point of the constellation Lynx — a serpentine formation of eight stars that stretches off to the right above the northwestern horizon for viewers in the Northern Hemisphere. Dark skies surrounding the new moon make Lynx much easier to trace, as it is often hidden in the glare of Earth's satellite.

Our final target is the glowing core of the Milky Way, which puts on a magnificent show between midnight and dawn in mid-May, as it arcs high over the southeastern horizon. A good way to spot the Milky Way is by locating the three bright stars Altair, Vega and Deneb, forming a famous asterism known as the Summer Triangle above the eastern horizon this time of year

The dense starfield and dark interstellar dust clouds of the galactic core appear as a glowing band passing through Deneb and between Vega and Altair, as it tumbles towards the horizon.

Read more: Learn the night sky without an app: May's easiest star-hops for beginners

Natural light pollution will be at a minimum, so why not also try to head away from bright city lights to make the most of the monthly pocket of darkness? You can use a trusted website like DarkSky.org to find your ideal stargazing location, along with smartphone astronomy applications like Stellarium or Star Walk 2 to find — or identify — breathtaking night sky objects and constellations in the night sky.

Want to capture your own gorgeous views of our galaxy? Then be sure to read our beginner's guide to photographing the Milky Way, along with our roundups of the top cameras and lenses for astrophotography.

Editor's Note: If you would like to share your dark sky astrophotography with Space.com's readers, then please send your photo(s), comments, and your name and location to spacephotos@space.com.

Spring is here and with it, a new set of sparkling constellations rises to prominence! But what are the stories behind these mesmerizing stellar citadels and how can you find them in the night sky?

Humanity's relationship with the stars stretches back for several millennia. In the modern day, we know the bright specks of their light to be incandescent orbs of glowing plasma powered by nuclear fusion, but in ancient times, the true nature of these stellar lanterns was a mystery.

Rather than allow the sea of stars to remain aloof, our ancestors chose to make them part of their world by linking them with storytelling and mythology. Countless cultures have imprinted their own cultural beliefs in the constellations, seeing mighty heroes, fantastic beasts and eclectic objects in the stars.

Read on to discover the mythology underpinning four popular spring constellations, along with tips on how to find them in the night sky. Be sure to check out our roundup of the best smartphone astronomy apps if you're new to the night sky, which can help you find everything from galaxies and nebulas to constellations and individual stars in the night sky.

BOOTES

Bootes has been associated with countless myths over the centuries. In Greek mythology, Bootes is often seen as a herdsman driving a great plow in the form of the nearby "Big Dipper" asterism. The constellation is also sometimes known as Arcturus — which is also the name of its brightest star — which translates roughly to "guardian of the bears", in reference to the constellations of Ursa Major and Ursa Minor, according to the Chandra Space Telescope website.

Ancient Chinese astronomers saw Bootes and Virgo as part of a larger formation of stars representing the horn of a great azure dragon, with Arcturus serving as its shining tip.

You can find the constellation Bootes using the famous stars of the Big Dipper asterism, which are located above the northern horizon throughout the year. Next, locate the three stars representing its "handle", and follow their curve out into space — a trick known to stargazers as the "arc to Arcturus". Follow that curve for roughly the length of the Big Dipper and you'll find Arcturus, the fourth brightest star in the night sky.

CORONA BOREALIS

The great arc of stars in the constellation Corona Borealis represents the crown of Ariadne in Greek mythology, who, in some tellings, marries the god Dionysus following the defeat of the bull-like minotaur in the labyrinth below the Aegean island of Crete by the demigod Theseus.

Australian aboriginal peoples, meanwhile, saw a great boomerang in the stellar formation, while the Native American Shawnee tribe envisioned dancing star maidens. The constellation was known as Al Fakkah to medieval Arabian astronomers, who saw in it a celestial bowl, per the University of Chicago.

The constellation can be found glittering roughly 20 degrees to the lower left of Arcturus in spring — about the width of two clenched fists held at arm's length against the night sky.

Corona Borealis may soon have a "new" jewel in its crown-like formation of stars, in the form of the symbiotic binary star system T Corona Borealis (T CrB), which periodically erupts in a powerful nova explosion, briefly rendering it visible to the naked eye in the night sky. T CrB could erupt any time now, with one study pointing at June 25 as a possible date for the anticipated nova outburst.

LEO

Many western stargazers now associate the stars of Leo with the Nemean Lion — a mythological beast that the ancient Greek hero Heracles was ordered to slay in penance for the killing of his family during a fit of madness, according to the telescope manufacturer Celestron.

Heracles swiftly discovered that the lion's pelt rendered it invulnerable to weapons, leaving him no option but to strangle the lion with his bare hands to end its reign of terror over the nearby town of Nemea. Zeus later placed the creature in the stars.

The ancient Persians, Babylonians, Syrians and Egyptians also drew comparisons between the stars of Leo and a mighty lion, according to the University of Chicago. The latter held Leo in particular high regard thanks to its association with the flooding of the river Nile, as the sun shone close to the constellation as the waterway broke its banks each year, according to EarthSky.

Leo is visible as a prominent sickle, or question mark-like formation of stars that can be found glowing in the southwestern sky at sunset in spring, with the bright star Regulus marking its lowest point for stargazers in the U.S.

HYDRA

Finally, we come to Hydra, the longest constellation in the night sky that, like the Nemean Lion before it, was brutally killed by Heracles over the course of his twelve labors, per the Chandra website. Heracles discovered the Hydra's den in the Lernaean Swamps with the aid of the goddess Athena and was able to break or sever its many necks — while using fire to prevent them from growing back — until only a single immortal head remained.

During the struggle, a giant crab came to the aid of the water snake and attacked Heracles, only to be crushed by the irate demigod! The goddess Hera — who despised Heracles — later set the crab in the heavens in the form of the constellation Cancer as a reward for its bravery.

It is thought that the Greek myth could be a retelling of an older Babylonian tale, in which the hero Gilgamesh slayed a colossal dog-headed, winged serpent known as a Mush-dragon.

To find Hydra, first locate the bright stars Chertan and Regulus in the constellation Leo and draw an imaginary line from the former to the latter, extending 20 degrees into open space. Here, you'll find a faint circlet of stars representing the head of the monster, along with a line of stars that weave their way towards the east, finishing not far below the blue-white light of the star Spica in the constellation Virgo.

Want to get a closer look at the treasure trove of wonders populating the night sky? Then be sure to check out our roundups of the best binoculars and telescopes available in 2026. If you're new to astronomy, our guide on beginning your amateur astronomy journey may come in useful.

"Look, there's the Southern Cross!" I turned, expecting an outstretched arm and a finger pointing low to the horizon. Instead, she was pointing at her phone. Her friend hurried over, not to look up, but to look down — both of them staring at a glowing screen while, just beyond them, Crux was visible in the night sky.

I wanted to interrupt them, to redirect their attention by a few degrees. Just lift your eyes! It's right there!

I didn't say anything, but that sad sight stuck with me. Smartphones are addictive. Yes, they're useful, but defaulting to an app after it's done its job gets in the way of the one skill that actually makes the sky make sense: naked eye star-hopping.

You don't need to try to recognize everything in the night sky at once.

Beginners often miss this and try to match the entire sky to a chart on a phone. It doesn't work because the sky is too big. To know it, you have to navigate it, starting with something obvious and moving to something less so, building a chain and, in time, a mental map. The night sky will reveal itself to you slowly if you let it, and it will be with you the rest of your life.

Sure, if you get stuck when stargazing, use an app. The point isn't to avoid technology entirely, but to avoid becoming dependent on it.

Why May is perfect for star-hopping

Early May is ideal for going app-free. This weekend, the moon fades toward last quarter, opening up darker skies with each passing night. This is the monthly observing window — when moonlight no longer overwhelms the fainter stars and the sky begins to reveal itself again.

The key to star-hopping in May is the most recognizable shape in the Northern Hemisphere's night sky — the Big Dipper/Plough. In May, its familiar seven bright stars are high overhead after dark, providing quick and easy reference for navigating everything else, with direct lines — literally — to Polaris, the North Star, and the great spring constellations of Leo, Virgo and Boötes, each anchored by a bright star that's easy to recognize.

How to go star-hopping

Instead of using an app, try these shortcuts — star-hops that teach you how the sky fits together, turning the sky into something you can move through instinctively.

Here are the ones to try this May.

1. Find Polaris from the Big Dipper

Start with the two stars at the edge of the Big Dipper's bowl — the "Pointer Stars," called Dubhe (pronounced DOO-bay) and Merak. Draw a straight line through them and extend it about five times their separation. You'll land on Polaris, below. It's not the brightest star, but it's the most important — marking true north and anchoring the entire northern sky. Once you've found Polaris, draw a line straight down to the horizon — that's due north.

2. 'Arc to Arcturus, spike to Spica.'

Follow the curve of the Big Dipper's handle in a smooth arc, and you'll arrive at Arcturus. Now take a spike to the next bright star — Spica (pronounced SPY-kuh). It's one of the most efficient navigational moves in spring stargazing.

3. Find Leo from the Big Dipper

Use the bowl of the Big Dipper as a guide. Draw an imaginary line from Dubhe and Merak — those two stars furthest from the handle — down toward the southern sky, and you'll arrive at Leo. Once you've located Regulus — Leo's brightest star — look for that distinctive backward question mark, called the Sickle of Leo (the lion's head), then trace the body eastward into a faint triangle. It's one of the easiest constellations to recognize once you've locked onto the "Heart of the Lion."

4. The Spring Triangle

There's a Winter Triangle and a Summer Triangle, so why not a Spring Triangle? Join Arcturus, Spica and Regulus, and you've created the Spring Triangle — a vast, unofficial asterism that anchors the entire southern sky in May. If you want to make it more equilateral, use the fainter star Denebola, at the back of the constellation of Leo, instead of Regulus.

5. The Spring Diamond

From Arcturus, look north toward the end of the Big Dipper's handle. About a third of the way along sits Cor Caroli, a dimmer star, but still the brightest in the tiny constellation Canes Venatici in an otherwise fairly empty part of the sky. Together with Arcturus, Spica and Denebola, Cor Caroli helps create the Spring Diamond asterism. Cor Caroli means Heart of Charles, thought to have been named in the 17th century for England's King Charles I.

Stargazer's corner: May 8-14, 2026

The moon is now waning and rising later each night, which means darker skies are back in the early evening. A highlight this May is Venus, which is climbing into the post-sunset night sky in the west. Later in the week, if you're out before dawn (a really early start!), the waning crescent moon reappears low in the east. However, the best way to use this week is to practice a star-hop or two, keeping sessions short and focused. Master one of them, repeat it, then stop. Repetition and familiarity are the keys to success in stargazing.

Constellation of the week: Boötes

Having followed the "Arc to Arcturus" from the Big Dipper, you're familiar with how to find the brightest star in the constellation Boötes — one of the oldest in the night sky. The rest of the constellation is said to form a loose kite pattern around Arcturus, stretching into darker regions of the sky. However, I always see Boötes as a champagne or cocktail glass. Maybe that says something more about me than the stars? More traditionally, Boötes is a herdsman or a plowman. An Arab legend saw Boötes as a herdsman to the Pole Star, while ancient Egyptians saw it as a Hippopotamus. Its anchor, Arcturus, is 37 light-years distant and a red giant star — its color leading Chinese astronomers to see it as a horn of a giant dragon.

My latest stargazing obsession

It's so easy to make excuses not to protect your night vision. You tell yourself you're only going outside for a few minutes or that checking an app on your phone for a few seconds won't make any difference. It will. Turn on a bright phone screen, and white light will flood your eyes, effectively rendering you star-blind. So if you think you may use a stargazing app while you're star-hopping, remember the golden rule before you go outside: dim your phone's brightness and put the app into red light mode, which is kinder to the rod cells in your eyes. Only then can you navigate the night sky with your night vision intact.

Editor's note: If you want to enhance your star-hopping game, take a look at our best binoculars guide.

The April new moon has arrived bringing several nights of spectacular dark skies perfect for observing the planets of the solar system, majestic constellations and the galaxies that lie beyond.

April's new moon occurs at 7:52 a.m. EDT (1152 GMT) on April 17, when the moon is positioned between the sun and Earth, rendering it lost from sight in the daytime sky, with the entirety of its near side bathed in shadow.

The moonless nights surrounding this phase are the perfect time to indulge in skywatching and night sky photography, as subtle constellations and deep sky objects often lost behind a veil of moonlight glisten in the twilight realm.

Visible planets

Look to the west shortly after sunset on April 17 to find Venus appearing as a bright evening star 15 degrees from the horizon, with the blue-white stars of the Pleiades open star cluster glowing 10 degrees above — roughly the width of your clenched fist held at arm's length.

The ice giant Uranus can be found a little under 5 degrees to the lower left of the star cluster. It'll be too dim to spot with the naked eye — without exceptionally dark skies and perfect vision — but a pair of binoculars or a small telescope will allow you to spot its disk as a tiny greenish dot, according to telescope manufacturer Celestron.

Jupiter, meanwhile, will shine high overhead, below Castor and Pollux — the brightest stars of the constellation Gemini. Turn a 6-inch telescope on Jupiter and you may notice a line of bright dots extending outward from the gas giant's colorful disk. Those are the Galilean moons Io, Ganymede, Europa and Callisto!

Head out an hour before sunrise on April 18 and find yourself a clear view to the eastern horizon for a chance to catch a planetary triangle rising in the glow of the coming dawn.

Mars will sit higher in the sky,with Saturn below and Mercury off to the right. Neptune will also be present to the upper right of Mercury, though the distant ice giant will be far too dim to spot with the naked eye.

Stars and constellations

The dark nights surrounding the new moon are a perfect time to explore some of the subtler constellations that glisten in the northern hemisphere sky.

First, locate the sickle-like formation of stars representing the head and chest of the great lion represented in the constellation Leo, which can be found high above the southern horizon in April with the bright star Regulus at its base.

Next, look to the lower right of Regulus to find a circlet of stars representing the head of the great serpent in the constellation Hydra, along with a string of stars that wind down and to the east towards the horizon, which mark its tail. Hydra is the largest constellation in the night sky, though it's often overlooked due to its lack of bright stars.

Perched along Hydra's back are the compact constellations Corvus (the crow) and Crater (the cup). To their east is the blue-white light of Spica — the brightest star in the constellation Virgo.

For a spot of deep sky viewing, why not head out to a dark sky location and sweep your telescope over the patch of sky where Leo, Virgo and the constellation Coma Berenices meet?

First, find Denebola, the star that marks the tail of the lion in Leo, and Vindemiatrix using a handy stargazing app. Roughly halfway between the two is Markarian's Chain — a spectacular string of galaxies whose ancient light can be spied with the aid of a modest telescope.

Read more: Galaxy season: Spring brings deep space wonder to the northern hemisphere night sky.

You could also capture spectacular images of the stars with the help of our beginner's guide to photographing the night sky. Be sure to check out our picks of the best telescopes and binoculars for exploring the night sky, along with our roundups of the top cameras and lenses for astrophotography available in 2026.

Editor's Note: If you would like to share your night sky photography with Space.com's readers, then please send your photo(s) along with your name, location and comments to spacephotos@space.com.

The blissfully dark nights surrounding this month's new moon phase on Feb. 17 present a perfect opportunity to explore the wonders of the post-sunset realm while free of the glare cast by our natural satellite.

A new moon phase occurs when the moon is positioned directly between the sun and Earth, meaning the moon isn't visible at night and is hidden by the sun's glare during the day. February's new moon phase occurred at 7:01 a.m. EST (1201 GMT), heralding the onset of a spectacular annular solar eclipse visible across a swathe of Antarctica, as the lunar disk passed in front of the sun, leaving only the "ring of fire" of its outer edge on display.

Sadly, unless you're a penguin or an Antarctic researcher, you were unlikely to catch the eclipse for yourself today. Still, the new moon offers several nights of pristinely dark moonless skies, so grab your telescope and join us on a sightseeing tour of the mid-February night sky.

Visible planets

Mercury will shine low in the west in the hour following sunset on Feb. 17, appearing as a bright "evening star" less than 20 degrees above the horizon. If you're incredibly lucky — and have a clear view of the western horizon — then you may be able to spot the steady light of Venus vying for attention in the glow of the setting sun below Mercury on Feb. 17, before it follows our parent star swiftly out of sight.

Saturn will be visible less than 15 degrees to the upper left of Mercury. Its iconic rings are finally starting to reveal themselves after seeming to "disappear" in November last year, when they turned edge-on in relation to Earth, making them appear as little more than a thin line.

Dark nights around the new moon phase are the perfect time to hunt twinkling constellations through the winter sky. Look to the left of Jupiter to find Castor and Pollux — the two stars that represent the twins in the constellation Gemini.

The gleaming star directly below Jupiter in the evening sky is Procyon, the brightest member of the constellation Canis Minor, the little dog. Sirius, the brightest star in the night sky, sits at the heart of Canis Majoris — the big dog — and can be found shining roughly 20 degrees to its lower right (roughly the width of two stacked fists held at arm's length), with the stars Wezen and blue Adhara forming its rear leg.

Both stellar hounds hunt the night sky alongside their master, the hunter depicted in the constellation Orion, the colorful stars of which can be spotted to the upper right of Sirius in the hours following sunset on Feb. 17.

Look out for the red giant star Betelgeuse, which marks the right shoulder of Orion and the blue supergiant Rigel, which marks the left foot. Between are the three familiar points of Orion's Belt, and hanging below that is the milky light of the Orion Nebula — a colossal stellar nursery that orbits within the Milky Way roughly 1,500 light-years from Earth.

To the right of Orion will be the red light of Aldebaran, the star which marks the eye of the great bull in the constellation Taurus. Notice a hazy patch of light to the upper right of Aldebaran? That's the Pleiades, a vast star cluster teeming with over a thousand blue-white stars, which makes for a magnificent target, whether you're viewing with the naked eye, binoculars, or a telescope.

Next, look to the northeast to find the seven stars of the "Big Dipper" asterism standing on its end close to the horizon. Locate the two uppermost stars — Merak and Dubhe — and draw an imaginary line from the former through the latter and out into space. The next bright star you find will be Polaris, the "North Star", around which the entire sky appears to revolve.

Continue following that line and look slightly higher to find the five bright stars of Cassiopeia, arrayed in a zig-zagging formation reminiscent of a sideways "W", or "M", which is said to portray a queen who was cast into the stars after falling foul of the Greek god Poseidon.

Want to get a closer look at the night sky? Then be sure to check out our picks of the top binoculars and telescopes for exploring the planets and constellations, while photographers should read our selection of the best cameras and lenses for astrophotography.

Editor's Note: If you would like to share your astrophotography with Space.com's readers, then please send your photo(s), comments, name and location to spacephotos@space.com.

During the winter season, two celestial dogs — the constellations Canis Major and Canis Minor — are on display in our evening sky.

If we begin to stargaze this week at around 6 p.m. local standard time, just as darkness has fallen, look for a 2nd-magnitude star rising about 30 degrees to the south of that point on the horizon marking due east. Your clenched fist held at arm's length measures approximately 10 degrees, so going roughly "three fists" to the right of east will bring you to this star known as Murzam. An imaginary line drawn through the stars Bellatrix in Orion and Alnitak (the lowest star in Orion's Belt), extended about twice its own length, also leads to Murzam.

This name, based on ancient Arabic, means "roarer" or "announcer." Its appearance on the horizon heralds the rising of the Dog Star Sirius, the brightest of all stars, about 17 minutes later. Both stars are a part of Canis Major, the Big Dog.

Interestingly, another star also serves to announce the appearance of Sirius: Procyon, the brightest star of Canis Minor, the Little Dog. The name Procyon is derived from the ancient Greek, meaning "before the dog" since it precedes Sirius by about 25 minutes as they rise. But later in the night, when they are toward the south, Procyon marches behind its more brilliant companion.

Dog days of summer

It is no wonder that the ancients would watch for Murzam and Procyon to announce the rising of Sirius, for a host of influences on man were attributed to the Dog Star and, by inference, to its constellation. Only the sun, the moon, Venus, Jupiter and occasionally Mercury and Mars, can rival Sirius.

As an example, the celestial dog was thought to aid the sun in causing the intense heat, drought and pestilence of summer. Sirius was said to be primarily responsible for the hot and muggy "dog days" that occur during July and early August for the Northern Hemisphere. Legend has it that because Sirius rises at the same time as the sun during the first half of summer, its brightness adds to the sun's energy, producing additional warmth. As it turns out, its heliacal rising (day of first visibility in the east before sunrise) occurred at the time of the summer solstice some five millennia ago.

Star of the Nile

The ancient Egyptians held a great deal of respect for Sirius. Its heliacal rising would herald the annual flooding of the Nile Valley, the waters re-fertilizing the fields with silt. This event was of such importance to them that it marked the beginning of their year. It, of course, was pure coincidence that for a time the rising of the brightest star in the sky should have coincided with the rising of the Nile River, but certainly the ancient Egyptians did not see it quite that way. After all, here was this brilliant star rising just before the sun, and shortly thereafter, they saw the Nile begin to rise. And this happened year after year, so naturally they concluded that it was the star that had a direct connection to the life-giving flood of their river. They called the star Sopdet, seen as a goddess, often depicted with a star on her head, and built temples oriented to the exact spot on the horizon where it would rise, for they believed that as it rose earlier at each passing morning, it was calling up the waters by its own mystical power and letting it flow across the plain.

Who let the dogs out?

If we wait until around 9:30 p.m., both Canis Major and Canis Minor will be in fine view, roaming across the south-southeast sky. The Big Dog is a rather striking star pattern, yet it is quite overshadowed by the brilliance of Sirius. All through the long winter nights, it scintillates with a dazzling white with a tinge of blue in the southern sky and because of its brilliance, it is always easily recognized. Follow the line of Orion's belt southeastward (toward the lower left), and you will come to this splendid twinkler. Seemingly, it appears as perhaps a stud on the Big Dog's collar or perhaps his tag. He also has a foreleg, and three rather bright stars lower down in a triangle forming his hindquarters, back leg and tail.

The star located in the lower right corner of the triangle is Adhara, which shines at magnitude +1.50 and ranks as the twenty-second brightest star and misses by just a hundredth of a magnitude, the cutoff for first-magnitude classification.

From a few fainter stars, you can perhaps make a head.

There was nothing tame about the dog of the heavens as conceived by the ancients. As late as the 9th century, Canis Major was pictured as a fierce, vicious hunting dog. It was not until 1603 that Johann Bayer (1572-1625) substituted a watchdog in his famous pictorial star Atlas Uranometria and other atlases thereafter followed suit. But the concept of both Canis Major and Canis Minor belonging to Orion appears to be as ancient as the Dog Star itself. The Big Dog is jumping up and down excitedly behind Orion, who is trying to deal with Taurus the Bull, who is charging down on him from his other side. We can only hope that the dog is indeed Orion's and coming to help him, and not to bite him!

As for Canis Minor, the Little Dog, he is certainly smaller, composed of Procyon — the Little Dog Star — and one other noticeable star, so this dog seems to only have a head and a tail. Thus, we have a pair of dogs running on either side of the Milky Way.

Tightly packed companions

Modern astronomers have discovered by a peculiar coincidence, in that each dog star keeps strange company. Both have dim, mysterious companions with unusual characteristics. They are white dwarfs, diminutive as stars go; the companion to Sirius (known as Sirius B or colloquially "The Pup"), for example, is only about the size of our Earth, about 7,500 miles (12,000 km) in diameter, yet contains nearly as much material as our sun. Hence, its average density is exceedingly high — an ordinary glassful of its material would weigh about ten tons if brought to the Earth's surface.

The companion stars were known to exist years before they were observed in a telescope. Both Sirius and Procyon are very near to us (8.6 light-years for Sirius, 11.5 for Procyon). In 1844, German astronomer, mathematician, physicist, and geodesist Friedrich Wilhelm Bessel (1784-1836) found their paths through space to be wavy, instead of straight, and correctly attributed this to the gravitational effects of unseen companions. In 1862, Alvan Clark (1804-1887) was testing the lens of a new 18½-inch refracting telescope, he saw Sirius B for the first time. Procyon's white dwarf companion was not found until 1896 at the Lick Observatory in California.

Personally, I think the discovery of these two amazing objects deserves a round of A-Paws.

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, Sky and Telescope and other publications.

When you look up at the night sky, you're gazing at stories written in stars.

Across cultures and centuries, constellations have been used to explain myths, guide travelers, and inspire dreamers. Each one carries its own symbolism, energy, and mystery, just like people do.

This quiz is designed to connect your quirks, strengths, and hidden sides with the constellation that resonates most with you.

So, are you ready to discover your cosmic twin? Step into the universe, answer a few revealing questions, and let the night sky tell you: What constellation am I?

Try it out below!

Constellations aren't just random dots scattered across the sky; they're ancient maps filled with myth, science and wonder.

From the heroic tales of Perseus and Andromeda to the zodiac signs that shape horoscopes, these star patterns have captivated cultures across the globe.

The stars have been guiding, inspiring, and storytelling for millennia — and now it's your turn to decode their secrets.

Whether you're a seasoned astronomer or someone who just enjoys spotting Orion's Belt on a clear evening, this constellation quiz is a chance to test your celestial savvy.

Try it out below and see how well you score!

The nights surrounding Aug. 29 are a great time to spot the stars of the famous 'Summer Triangle' asterism, bisected by the glowing band of the Milky Way, with an early-setting crescent moon providing a perfect setting for the stellar hunt.

Each of the stars of the Summer Triangle belongs to a separate constellation in the night sky. Altair, the lowest point of the triangle, can be found twinkling to the left of the Milky Way in the constellation Aquila, high above the southern horizon after sunset in August. Blue-white Vega, the brightest star of the constellation Lyra, sits to its upper right on the opposite side of the ribbon of dust, gas and stars representing the galactic disk.

Deneb, which forms the tail of the swan represented by the constellation Cygnus, appears to be embedded directly in the hazy profile of the Milky Way, completing the triangle formation.

The 6-day-old 40%-lit moon sets less than three hours after sundown on Aug. 29, presenting a clear sky in which to explore the majesty of the stellar trio. Each of the stars has been subjected to intense scientific scrutiny over recent decades, revealing fascinating insights into their diverse natures.

Vega, for example, is only 450 million years old — a child compared to our 4.5 billion-year-old sun — and spins so fast that it completes a full rotation once every 12.5 hours, just 10% under the critical rotation speed that would see it rip itself apart.

Altair, meanwhile, orbits within the Milky Way just 16.3 light-years from Earth, making it one of the closest visible stars in our night sky, while supergiant Deneb is doomed to one day evolve into a red giant star, before ending in a dramatic supernova explosion.

Want to learn the asterisms and constellations of the night sky by heart? Then be sure to check out our guide to the best smartphone astronomy apps, which use augmented reality technology to point the way to both stars and deep sky objects alike.

This has been a most interesting year to follow Mars. If you've been monitoring the Red Planet since the start of 2025, you have no doubt noted the dramatic change in its brightness as well as the occasional interactions it has had with the moon, bright stars and other celestial objects.

Mars travels a little more than half of its orbit each Earth year, and thus has oppositions (that point in the sky where it appears directly opposite to the sun in the sky) every two years plus about 50 days (its "synodic period," which is also the longest for any known planet). Prior to 2025, the last opposition of Mars was on Dec. 8, 2022; after 2025, the next will come on Feb. 19, 2027. It reached opposition this year on Jan. 16 and two nights earlier, on Jan. 14, a nearly full moon passed directly in front of Mars as seen from much of North America.

Mars is the most Earth-like planet of all known beyond our own, and it passed closest to Earth during the American morning of Jan. 12, just 3.5 days before opposition.

An "off year" for the Red Planet

But the 2025 apparition of Mars has been one of the poorer and more distant ones in the planet's 15-to-17-year cycle of oppositions near and far. Just three months after opposition, Mars arrived at aphelion (farthest from the sun) in its eccentric orbit, so we came no closer than 59.7 million miles (96.1 million kilometers) to it last winter — some 5.3 light minutes away. Shining with a yellow-orange hue, it attained its peak brightness, gleaming at magnitude -1.3. That's just a trifle fainter than Sirius, the brightest star in the sky.

Ever since Jan. 12, however, it has been receding from Earth, and consequently it has gradually been getting dimmer. So, we're leaving it behind, and ever since Feb. 24, Mars has been traveling in prograde (eastward) motion — a long, straight line around the sky, becoming steadily farther away and smaller. Still, in spite of its fade-down, it continued to put on an eye-catching show during February and March with the "twin stars" of Gemini, Pollux and Castor as the brightest member of a prominent, albeit temporary, triangle.

And then, on the evening of May 4, Mars made a very close pass near the Beehive Star Cluster (M44), a very pretty sight as viewed through binoculars or a low-power, wide-field telescope.

And during the latter part of June, Mars will again make for a couple of eye-catching shows, teaming up first with a bright star and then, late this month, with Earth's nearest neighbor in space.

A close conjunction with Regulus

Mars now appears as nothing more than a featureless dot in most telescopes. But on Tuesday evening (June 17), it forms a wonderful naked-eye pairing with the thin, only slightly brighter star Regulus in the constellation of Leo the Lion. Observers in the Americas will see the planet and star 2 degrees apart or less from June 13 through June 20, and one degree or less apart June 15 through June 18.

For viewers, around 40 degrees north latitude, Regulus and Mars are side by side, only 1.5 degrees apart on June 14, and Mars is 45 arc minutes (three quarters of one degree) almost straight above Regulus on June 17. That will be the evening when they are closest together. Neither one is exceptionally bright; Regulus shines at magnitude +1.34 and Mars is at magnitude +1.41. But the fact that they will appear so near to each other and are so closely matched in brightness will make them appear to stand out in the early evening sky.

Look for them around 10 p.m. local daylight time, roughly one-quarter up in the western sky. In addition to their closeness to each other, look for the orange-gold of Mars and blue-white of Regulus to appear intensified by contrast to each other when they are so close together (as seen with the naked eye or binoculars).

Don't miss this near miss!

On Sunday evening, June 29, a waxing crescent moon, 24% illuminated by the sun, will pass very close to Mars and make for a rather attractive sight, low in the western sky at dusk. The moon, moving around Earth in an easterly direction at roughly its own diameter each hour, will appear to pass just below the orange-gold planet. Even though North America will miss out on seeing the moon pass directly in front of Mars (called an "occultation"), Mars will attract attention as it slowly appears to glide above the moon.

The view of the moon occulting Mars will be restricted to parts of Ecuador and Peru.

After closest approach, the moon will move slowly away from Mars. Locations to the east (or to the right) of a line running roughly from central Texas through central Ontario will be in various stages of twilight at the moment that the moon and planet are closest together (called a "conjunction").

To the west (or to the right) of that line, the sun will be above the horizon when the two are in conjunction, but will still appear relatively close as darkness falls. For places where the two are closest together within an hour or less after sunset, you'll probably initially need binoculars to pick Mars out against the bright twilight sky.

Once the sky has sufficiently darkened, however, Mars will be relatively easy to see. For most locations, the upper limb of the moon will skim to within about 20 arc minutes (one-third of a degree) of Mars. For places across the northern U.S. and Canada, the gap between the two will be a bit larger, while across the southern U.S. and the Caribbean, the gap will be a bit smaller.

The table below (calculated exclusively for Space.com by Joe Rao) provides the specific details for 15 selected cities in the U.S. and Canada.

The table gives civil times (all p.m.) of Mars' closest approach to the edge of the moon's upper limb. Separation between Mars and the moon's upper edge is given in terms of minutes of arc (the apparent width of the moon on June 29 is 31 arc minutes), and the percentage of the apparent width of the moon. A value of 0.48, for example, is equal to 48% of the moon's width (or fractionally, slightly less than one-half).

Examples: from Miami, closest approach between Mars and the moon is at 10:13 p.m. EDT. Separation is 15 arc minutes or 0.48, which is just under one-half of a moon's width from Mars to the upper edge of the moon. From New York, closest approach is at 9:48 p.m. EDT, the separation is listed at 23 arc minutes or 0.74, which means that 74% of the moon's width will separate Mars from the moon's upper edge.

Where do we go from here?

After its rendezvous with the moon, Mars will continue to press on to the east. In the weeks and months that follow, Mars will continue to be a fixture in the evening sky, but will continue to recede from Earth and consequently will get fainter, diminishing to the rank of second magnitude.

Passing north of Spica on Sept. 13 and Mercury on Oct. 19, Mars will be getting progressively lower in the sky — more southerly and nearer to the sunset. When it finally fades into the evening twilight glow of early November, it will be on the far side of the sun, some 225 million miles (362 million km) from Earth and just 1/13 as bright as it was in mid-January. It will finally end its run as an evening object when it will be at conjunction with the sun next year, on Jan. 9.

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, Sky and Telescope and other publications.

We're here to help you reach for the stars and complete the NYT Strands puzzle for today, April 25, 2025.

Fans of word puzzles like Wordle or Connections definitely have to give Strands a go. In this game, you're presented with a jumbled grid of letters where you must join them together to create words all linked to one topic know as the spangram – one or two words that span from opposite sides of the grid to reveal the puzzle's theme.

Today's theme hint is "It's in the stars" and there are seven theme words to be found, plus the spangram. If you're a bit stumped with Strands, then these constellations will help shine some light on the problem.

Spoiler warning: Below there will be information about today's New York Times Strands puzzle.

Ursa Major

The largest constellation in the Northern Hemisphere is the aptly named Ursa Major constellation: the Great Bear. Here you'll be able to spot one of the most recognizable collection of stars in the sky, the Big Dipper. Throughout history it's been used as a compass, a clock, a calendar and even a ruler … and now it'll help you solve today's NYT Strands puzzle.

Orion

Orion, the "Hunter" constellation, can be seen in both the Northern and Southern hemisphere thanks to its location on the celestial equator. Your eyes will be drawn here to Rigel (Beta Orionis) and Betelgeuse (Alpha Orionis), two of the brightest stars in the sky.

Cygnus

One of the most beautiful constellations in the sky is the celestial swan, Cygnus. The Milky Way galaxy runs through Cygnus and is easy to find thanks to the shape of the Northern Cross at its center. Cygnus is also notable for containing Cygnus X-1, the first known black hole.

Centaurus

Alpha Centauri, the nearest star system to our solar system, can be found here in this constellation. Centaurus is named for the mythical half-man, half-horse creature, the Centaur. There is also one other centaur star pattern found in our night sky: Sagittarius, the Archer.

Virgo

There are twelve constellations of the zodiac and Virgo is the largest of them. In fact, it's the second-largest constellation in the sky. Virgo means "virgin" or "maiden" in Latin.

Crux

Within the constellation Crux is an asterism called the Southern Cross. Throughout history this has been an essential guide for navigators as two of its major stars (Gacrux and Acrux) line up to point towards the South Pole.

Scientists announced on Friday (April 18) that the newest solar investigator in town has captured its first-light images — or should I say the newest solar investigators. That is, this NASA sun-studying mission, named PUNCH, is technically made up of four small satellites that are strategically distributed in our planet's orbit. The quartet is designed, however, to work together as a single instrument with the power to decode some of our star's biggest mysteries.

"All four instruments are functioning as designed. We're excited to finish on-orbit commissioning and get these cameras working together," Craig DeForest, at the Solar System Science and Exploration Division of the Southwest Research Institute (SwRI) in Boulder, Colorado, said in a statement.

What you're seeing in these images is a bunch of stars, visible as faint sparkles against a dark sky, enshrouded by a soft amber haze. This lovely luminescence is known as the "zodiacal light," which is a diffuse glow created by dust particles orbiting the sun reflecting sunlight toward Earth. If you look closely at the stars, there are even some constellations visible in the scene, like Taurus and Cetus. However, if all goes to plan, PUNCH's future cosmic images won't have any stars at all — or any zodiacal light, for that matter.

The ultimate purpose of PUNCH is to use its four instruments — three wide-field imagers (WFI) and a near-field imager (NFI) — to isolate features found within the solar wind. This is because one of the big sun mysteries that the mission aims to solve is the puzzle of how the sun's outer atmosphere, or corona, turns into the solar wind.

If you can imagine an invisible bubble around our cosmic neighborhood, aka the barrier between our solar system and the rest of the universe, that entire bubble is filled with streams of charged particles released from the solar corona. The filling of that bubble is the solar wind, and the bubble itself is known as the heliosphere.

But to come to conclusions about the transition between solar corona, the solar wind and the heliosphere, scientists need to isolate extremely faint features within all the solar material — and to isolate those features, there can't be any interference like background stars or zodiacal light.

"Throughout the commissioning phase, the PUNCH team is calibrating the NFI data to remove 99% of the light to show materials streaming out from the sun's outer atmosphere in stunning detail," DeForest said. "The three WFI 'first-light' images show star fields, but the ultimate goal is to remove the star field and other background light and preserve the faint glimmer of the solar wind as it travels to Earth."

What these first-light images prove, however, is that the instruments are usable and working in such a way that this process can happen. According to the statement, one NFI and one WFI were activated on April 14, and the other two NFIs were activated on April 16.

Once everything seems to be going well, we'll hopefully get a look into how PUNCH is meant to take advantage of a property of light called polarization.

"A polarimeter is a camera that can measure polarized light like you might see through a pair of polarized sunglasses, and we use that to measure what we're imaging in three dimensions," DeForest previously explained in a press conference. "As we look at the solar wind, we're looking at sunlight that's scattered off the actual material that we're seeing. That scattering process polarizes the light, and the degree of polarization tells us where the object was in three dimensions."

Furthermore, it would appear that during the PUNCH mission's 90-day commissioning period, the team managed to demonstrate the capabilities of new "water-powered, shot-glass-sized" rocket engines. These engines, which the team says can carry safe and nontoxic propellant, work by the spacecraft passing an electric current through water to create stores of high-pressure hydrogen and oxygen. That hydrogen and oxygen can then burn as fuel when the team needs to correct any of the spacecrafts' trajectories.

DeForest says the "safety and stability" of this propulsion system is worth it, likely because, as the statement explains, each of the satellites will need to maneuver hundreds of times to maintain proper position.

PUNCH launched on March 11, sharing a SpaceX Falcon 9 rocket ride to Earth orbit with NASA's SPHEREx mission (which is basically like a wide-angle James Webb Space Telescope). After PUNCH's commissioning phase finally comes to a close, the team says we should be seeing scientific information start pouring out this summer; data analysis is set to begin in June.

On Saturday evening (Oct. 5) as darkness is falling, be sure to take a look low toward the west-southwest part of the sky for a beautiful celestial tableau formed by a lovely crescent moon and the brilliant planet Venus. 

The moon will appear to hover about 4-degrees below and to the left of Venus. Your clenched fist held at arm’s length measures roughly 10-degrees. So, the moon and Venus will appear to be less than a "half a fist" apart. These Venus-moon rendezvous occur on roughly a monthly schedule. Indeed, if Venus were stationary and did not appear to move against the star background, then a Venus-moon encounter would occur every 27 days, 7 hours and 43 minutes. 

This is called a "sidereal month" which is the length of time it takes the moon to circle the Earth once, using the background stars as a reference point. So, we try to apply the "sidereal month rule" to this schedule, then the next time Venus and the moon should appear to pair-off would be on Nov. 1. 

But if you go out and face west-southwest soon after sundown, you'll see Venus, but the moon will be nowhere to be found. What happened?

Venus on the move

Of course, that rule won’t work because Venus is not stationary, but is moving in its own orbit around the sun. In fact, the next time that the moon will pass Venus will come on the evening of Nov. 4. From our earthly viewpoint, Venus will appear to move considerably to the east against the star background.  

On Monday night (Oct. 7), Venus will be in the constellation Libra, the Scales. But by next month – on Nov. 4 – it will have appeared to have moved about 38-degrees to the east where it will then reside in the non-zodiacal constellation Ophiuchus, the Serpent Holder.  

Related: The next solar eclipse will be a partial eclipse in March 2025

So, the moon had to travel that much more across the sky to catch up to Venus.  Since the Moon appears to move across the sky at roughly 13-degrees per day, it needs three more days (13 x 3 = 39) to catch up to Venus.  

Indeed, on Nov. 4, we will once again we will be treated to an eye-catching sight in our western twilight between the two brightest objects in the night sky. 

And we're moving too! 

Incidentally, another factor that must also be considered is our own Earth's movement around the sun.  If, in fact, you do look for the crescent moon on Oct. 30 you won't see it because it will be at new phase and hence too near to the sun to be seen.  That’s because during the 27 days following Monday night's Venus-moon pairing, the Earth’s movement around the sun will cause the sun’s position in the sky to shift to the east as well.  

And so, in this particular case, come Nov. 4, the sun will appear to have shifted right into the very same region that Venus and the moon occupied on Oct. 3.  Of course, by Nov. 4, the moon will have moved well clear of the sun and once again will be readily visible in the west-southwest along with Venus.  

Lustrous evening star 

Now gleaming at magnitude minus 4.0, Venus in the coming weeks and months will ascend dramatically higher in the western sky and by New Year's Day it will be setting more nearly 4 hours after the sun. And by February it incredibly will gleam twice as bright as it shines now. 

No other star or planet can come close to matching Venus in brilliance, not even brilliant Jupiter which currently is hidden in the glare of the sun. During World War II, aircraft spotters sometimes mistook Venus for an enemy airplane. There were even cases where Venus drew antiaircraft fire.  

And from Thanksgiving through Presidents' Day, it will dominate our evening sky.

Also look for the southern claw 

Lastly, in addition to Venus teaming up with the moon, it will also be passing rather close to a most notable double star. A low-power scope can also reveal the wide double star Alpha (α) Librae (Zubenelgenubi). This star's tongue-twisting name is derived from the Arabic al-zubānā al-janūbiyy which means "the southern claw." While this star now belongs to the zodiacal constellation of Libra the Scales, at one time in the distant past, it marked the tip of the southern claw of Scorpius the Scorpion.

On Saturday evening, Venus and this star will be less than 1-degree apart. Binoculars will be beneficial in seeing all three: moon, Venus and star against the bright twilight sky.

If you're looking to get a closer view of Venus, the moon and other night sky objects, our best telescopes for beginners guide can help you find what you need. And if something more handheld is your preference, check our our best binoculars guide.

Editor's note: If you take a stunning photo of Venus and the moon and want to share it with Space.com, send images and comments to our skywatching inbox at spacephotos@space.com.

One of the best ways to check whether summer has arrived is to look at the eastern sky after it gets dark. Climbing above the horizon at this time of year is a group of stars called the Summer Triangle, a vast but simple arrangement of three very bright but very different stars.

Not only does its arrival in the night sky signal the beginning of summer in the Northern Hemisphere and winter in the Southern Hemisphere (where it's known as the Winter Triangle), but this triangle marks where to look for the Milky Way if you are under dark skies this season.

The Summer Triangle is not a constellation but an asterism, a simple pattern formed by stars from official constellations. It includes one bright star from each of three constellations — Vega in Lyra, Deneb in Cygnus and Altair in Aquila. 

The Summer Triangle star that you will see rising in the east after dark is Vega. It's one of the most famous in the night sky and one of the brightest, largely because it's so large and so close — just 25 light-years distant from the solar system. If you have a good pair of stargazing binoculars, first train them on Vega, then range slightly to the northeast, and you will see Epsilon Lyrae, a showpiece double star. However, with a backyard telescope, each star is also revealed to be a double star, earning it the nickname "the Double Double." 

Related: Full moon calendar 2024: When to see the next full moon

Rising below and to the right of Vega on the horizon is Altair, the 12th brightest star in the night sky. Like Vega, it's bright because it's close, a mere 17 light-years away from Earth. Like Vega, Altair is about twice the mass and radius of the sun. 

That's not the case for the third star in the Summer Triangle, Deneb, which is visible rising to the northeast. It's the 19th brightest star in the night sky, but much further away than Vega and Altair at 2,600 light-years away. It's so bright because it's a supergiant star 20 times the mass and around 200 times the radius of our sun. It's one of the farthest stars that can be seen with the naked eye.

The Summer Triangle is worth finding and following throughout the summer as it climbs higher into the sky each night. It's across a rich field of the Milky Way, so if you're in a dark sky park or anywhere with low levels of light pollution, find the Summer Triangle, and you'll see the Milky Way running through it, from Deneb to Altair. 

When we look up at the night sky, we see familiar stars and constellations that have been visible for thousands of years. Yet stars do not last forever. They live and die, though on exceptionally long timescales. But how long will it take for these changes to be visible in the constellations visible from Earth? 

Much of this depends on the lifetimes of certain stars. Most stars in our galaxy are small. However, in the constellations we see, large and bright stars are overrepresented. The larger the star, the shorter its lifetime and the sooner it will disappear from our sky. 

Stars about eight times the size of the sun and larger will undergo a core-collapse supernova at the ends of their lifetimes. These massive explosions are impressive sights and signal stars disappearing from our sky. 

Related: Can you see stars in light-polluted skies?

Many astronomers think Betelgeuse, a red supergiant star, will be the first star to disappear from our sky. It could vanish tomorrow … or 100,000 years from now. When it explodes, it will be brighter than the full moon — bright enough to be seen during the day or cast shadows in the night. 

Another star of interest is Eta Carinae, which is visible mostly from the Southern Hemisphere. This binary star system is hundreds of times the mass of the sun. Around 180 years ago, Eta Carinae experienced a massive outburst. The star survived, but its next outburst may result in a supernova that destroys the star. 

It's difficult to predict the exact moment these stars will explode, but one clue could come from ghostly particles called neutrinos. During a supernova, most of the energy is not in the optical but rather emitted as neutrinos. 

"The neutrino production from Betelgeuse will ramp up in the last phases of its life so that in the last day, it will emit enough neutrinos that our current detectors will see it," said Brian Fields, a supernova expert at the University of Illinois. We'll have about 24 hours' notice before the star explodes. 

Such a massive explosion may sound dangerous to Earthlings, but we're too far away for it to have an impact, Fields said. For life on Earth to be affected, a supernova would have to be within 8 to 10 parsecs — about 2 million times the distance between Earth and the sun. 

"If we had anything that close, it would be by far be the brightest star in the sky," Fields told Space.com. "They're not subtle. They don't sneak up on you."

On the move

Although a supernova may be more dramatic, our constellations will undergo a more radical change from the movement of stars. 

Every star in our galaxy is moving. When viewed from Earth, this is called proper motion, which is how much the apparent location of the star seems to change. Barnard's star is the fastest star, whipping by at 10 arc seconds a year. This means that in 180 years, the star moves the diameter of the full moon. 

Most stars travel much more slowly than that. So the constellations we see today are basically the same as the ancient Greeks saw them. Over tens of thousands of years, however, stellar motions will add up to radically affect the shapes of the constellations. 

Take the Big Dipper, which is an asterism in the constellation Ursa Major. The central five stars of the Big Dipper not only appear close together in our sky but are physically close to one another as well. Born together, these stars are a "moving group" that travel across the sky together. The stars on each end, however, have their own directions and motion.  

"Over time, the Big Dipper will morph and won't look like a spoon at all," Fields said. "Enough of it will change that it will look 'freaky deaky' after tens of thousands of years."

Because these changes will be visible over timescales of tens of thousands of years — rather than tens of millions of years, which is the timescale in which we expect many supernovas — our constellations will be affected by proper motion long before the stars vanish from the sky. 

Earth's motion will also affect our night sky. Our planet wobbles like a top, changing the direction of the North Pole. This is called precession. 

"The Egyptians used to have a different north star," said Kayleigh Excell, a supernova researcher who works with Fields. "At the time of the Pyramids of Giza, [their north star] would be Alpha Draconis," also known as Thuban.

Our constellations will change, but not just because stars die or move. New stars are actively being born in our galaxy. These stars will eventually emerge from their nebulas. If they're bright enough, these stars will take their place in new constellations in our sky.

If your household is like most American families, then on Thursday (Nov. 23) you likely will be sitting down with family and friends for a traditional Thanksgiving turkey dinner during the mid-to-late afternoon hours.  

Then, as darkness falls, some of you will probably migrate into the living room to catch some football or other holiday fare on television. But if you have a large gathering of family and friends at your home — and if your skies are mainly clear — why not invite everyone outside to gaze at the evening sky?  

If you have binoculars, or better yet, a telescope, you just might end up turning this into a memorable family tradition of its own.

Related: Best telescopes for deep space 2023: Spy early Black Friday telescope deals

The moon 

This year, on Thanksgiving evening, about 90 minutes after sundown, the moon will be at a waxing gibbous phase, four days before reaching full phase, 85% illuminated and shining brightly well up in the southeast sky. 

You might assume that the best time to look at the moon through a telescope is when it's at full phase, but that's probably the worst time to look at it. When the moon is full, it tends to be dazzlingly bright, as well as flat and one-dimensional in appearance. 

In contrast, a gibbous moon is when we get a better view of the lunar landscape right along the sunrise-sunset line, or terminator.

The terminator is that variable line between the illuminated portion and the part of the moon in shadow. Along with the fact that a gibbous moon offers more viewing comfort to the eye than a full moon does, using a telescope with just small optical power (magnifications of 20x to 40x), or even good binoculars, we can see a wealth of detail on its surface. Around those times when the moon is half-lit or in its gibbous phase, those features lying close to the terminator stand out in sharp, clear relief.

Related: Night sky, November 2023: What you can see tonight [maps]

And two bright planets

Along with the moon, we also have two prominent planets in the Thanksgiving night sky. 

Due south, we can see Saturn, shining with a sedate, yellow-white glow about one-third up in the south-southwest sky. With a telescope magnifying 30x, the famous rings begin to come into view. If you have a 4-inch (10 centimeters) telescope, a 100x eyepiece will readily bring Saturn's most famous appendage into view.  

Meanwhile, far brighter and standing about one-third up in the eastern sky will be Jupiter, appearing like a dazzling, silvery-white, non-twinkling star. You'll see it glowing 20 degrees to the lower left of the moon. Since your clenched fist held at arm's length measures roughly 10 degrees, Jupiter on this night will be about "two fists" to the moon's left. 

Steadily held binoculars will provide a glimpse of the four big Galilean satellites, first glimpsed by Galileo Galilei in 1610. A telescope will easily show the disk of the biggest planet in our solar system — 11 times wider than our Earth — with all four moons in view on one side of the big planet on this holiday night.

Going outbound from Jupiter, we can see Io, Europa, Callisto and Ganymede.

Stars of late autumn

If we concentrate on the stars and constellations, it's interesting to note that many of the star groups and rich Milky Way fields of summer evenings are still very much evident in the western part of the sky, while the brilliant yellow star Capella ascending in the northeast is a promise of even more dazzling luminaries to come. For, in just another few weeks, Orion and his retinue will be dominating our winter skies. 

Still very well placed high in the west is the Summer Triangle, a roughly isosceles figure composed of the stars Vega, Altair and Deneb.  As we move deeper into the autumn season and the evenings grow chillier, this configuration sinks lower and lower in the west. If you have binoculars, invite family and friends to use them to sweep among the splendid star fields of the Summer Triangle. They may very well share Galileo's awe of more than four centuries ago, when he first turned his telescope on the myriad faint stars that compose our Milky Way. 

Looking high in the south-southeast — almost overhead — are the four bright stars that compose the Great Square of Pegasus, a landmark of the autumn sky. And if you have a clear view of the northern horizon, it is there you will find the familiar Big Dipper, looking abnormally large due to the "moon illusion," which makes, the sun, the moon and even star patterns like the Dipper appear larger than normal when they are situated near the horizon. 

Meanwhile, the striking zig-zag row of five bright stars forming the "M" of Cassiopeia, the Queen, soars high above the Dipper in the north.

Looking back in time

The very first Thanksgiving is said to have taken place in the year 1621. We see many stars whose light started its immense journey before our country was born. Are there any stars that are around 400 light-years away? 

Because of the difficulty in measuring parallaxes (distant objects' changing positions when viewed from Earth), astronomers cannot determine such distances with an accuracy of one light-year. However, in its table of the 288 brightest stars, the 2023 "Observer's Handbook" of the Royal Astronomical Society of Canada lists two that are about 400 light-years away and are above the horizon on November evenings: third-magnitude Algenib, the star in the lower left corner of the Great Square of Pegasus, and second-magnitude Almach, at the end of the chain of stars marking the constellation of Andromeda, the princess. 

If you see either of these stars on your next clear night, keep in mind that you are looking at light that started on its journey to Earth at about the same time that the first pilgrims were arriving in what we now call the state of Massachusetts. 

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, the Farmers' Almanac and other publications. Follow us on Twitter @Spacedotcom and on Facebook. 

Imagine going back thousands of years and showing off the cool astronomical functions of your smartphone. It can tell the date and time with incredible accuracy. It can pinpoint your location. It can even pull up a map of the stars, tell you the phases of the moon, and predict the next major astronomical event.

These ancient people would be amazed, right? It turns out, they probably wouldn't be all that impressed — because they could do all of those things, too.

The most recent example of a portable, all-in-one, multifunction astronomical tool is the astrolabe. From the Greek words for "star" and "taker," the astrolabe was used from ancient times all the way up to the early modern period. A useful tool and fashion accessory rolled into one, the astrolabe was a solid disk of metal with a series of dials, pointers and engravings. The astrolabe could do it all for the wandering type: It could tell the time of day based on the sun's position, provide coordinates based on the positions of certain guide stars, predict when the sun would rise or set, and more. As with your smartphone, you wouldn't ever want to leave home without it.

Related: Mariner's astrolabe from 1503 shipwreck is world's oldest 

Prior to the development of the highly portable astrolabe, ancient people still had high-precision instruments, but they were usually either larger or closely guarded by a few key individuals. One example is the Antikythera mechanism, which dates back to around 200 to 100 B.C. and was discovered in a shipwreck in 1901. The complex set of gears within the mechanism allowed the user to predict lunar eclipses, track the movements of all the visible planets, tell you when certain Olympic-style games were scheduled to happen, and calculate two very critical cycles: the Metonic and Saros cycles.

The Metonic cycle arises from the fact that a single solar year (the time between one spring equinox and the next) is almost, but not quite, the same length as 12 complete lunar months (the time between one new moon and the next). Since ancient times, astronomers have quickly noted the regularity and predictability of these two separate rhythms in the sky, and ancient calendars place a lot of emphasis on translating between lunar and solar calendars, especially for scheduling feast days to close any gaps. Every 19 years, however, the lunar and solar calendars resynchronize on their own, which is known as the Metonic cycle, so it was helpful to know where you were in that cycle.

The Saros cycle measured the time between eclipses, whether a lunar or solar eclipse. Roughly every 223 lunar months, or 6,600 days, an eclipse repeats. Ancient people didn't have the sophisticated understanding of gravity to predict if the eclipse would be full or partial, but they did have enough astronomical knowledge to recognize that if an eclipse happened, there was a good chance of another one happening 6,600 days later.

An example of the importance of these kinds of cycles can be seen in the Berlin gold hat, an artifact dated to 1000 to 800 B.C. The tall, cone-shaped hat is adorned with repeated motifs of astronomical symbols and was obviously meant to be worn in religious and/or political ceremonies. The hat is just big enough to contain an entire Metonic cycle depicted in its rows — a handy tool when you might be responsible for maintaining your community's religious calendar.

Humanity's ability to track and monitor celestial cycles stretches back into prehistory, as well. Perhaps the most famous astronomical monument is Stonehenge, dated to 3000 to 1500 B.C. The alignment of special "keystones" allowed observers to mark the precise date of solstices, signaling the beginning of new years and new seasons. If you've ever been stuck inside all winter, where each day feels exactly like the last and you've lost track of when spring will ever arrive, you can appreciate our ancestors' desire to make a giant clock out of stone to solve that problem.

The oldest alleged calendar is a carving found on an ivory mammoth tusk, dated to an astonishing 30000 B.C. While there is debate about what the carvings mean, one side features a figure of a man, who holds a pose suspiciously similar to the constellation Orion (which, by the way, almost all cultures around the world associate with a person). On the opposite side are 86 markings. While hotly debated, one potential explanation for the number 86 is that the typical human pregnancy lasts one year, minus 86 days. And it just so happens that at the location where the tusk was found, the star Betelgeuse, the shoulder of Orion, is visible above the horizon for 86 days every year. 

Perhaps those prehistoric people found a connection between the motion of this celestial object and our Earthly rhythms — something we have preserved to the modern day, every time we set our schedule to the rising and setting of the sun and the annual cycle of the seasons.

A relatively newly discovered comet makes for a tantalizing skywatching target this summer. 

Comet C/2023 E1 ATLAS was discovered in March 2023 by the Asteroid Terrestrial-Impact Last Alert System (ATLAS), which is funded by NASA and operated by the University of Hawaii. This array of four telescopes spread out in Hawaii, Chile and South Africa scans the sky for near-Earth objects in order to warn of any potential hazards heading Earth's way.

While not particularly bright, the comet will be fairly easy to spot for Northern Hemisphere skywatchers, high in the skies throughout the summer near Ursa Minor, the Little Dipper. Comet E1 ATLAS reaches perihelion, its closest point to the sun, on July 1. 

Related: Comets: Everything you need to know about the 'dirty snowballs' of space

By the time July's new moon arrives on July 17, the comet will be approaching its maximum brightness and will have moved eastward toward the constellation Cetus, the Whale. If you go looking for the comet yourself, don't expect to see a bright green snowball with a well-pronounced tail; through most backyard optics, the comet will likely appear as a hazy, greenish smudge.

When comet C/2023 E1 (ATLAS) was discovered, it was quite faint at just magnitude +19 (the lower the magnitude, the brighter the object). It has since brightened to around magnitude +10, enough to be spotted with binoculars and most medium-sized telescopes, but still too dim to be seen with the unaided eye. The comet is expected to reach a maximum magnitude of +8 or +9, still fairly dim compared to many other night sky sights.

Nevertheless, comet C/2023 E1 (ATLAS) has proven photogenic to patient astrophotographers. Austria-based comet hunter and astrophotographer Michael Jäger has imaged C/2023 E1 (ATLAS) on multiple occasions, and has been able to capture its somewhat dim tail:

In a 100-minute exposure taken on June 18, Jäger captured an image that shows the comet's motion relative to the background behind it.

Astrophotographer and astronomy educator Dave Eagle caught an image of the comet on June 26 from Raunds, England.

And comet hunter and amateur astronomer Taras Prystavski imaged the comet from the Great Basin Desert in Utah on June 23, showing the comet's characteristic green glow in clear detail.

Want to see comet C/2023 E1 (ATLAS) or capture stunning your own images of comets and other objects in the night sky? Our guides on the best telescopes and best binoculars will help. 

Learning about the best cameras for astrophotography and best lenses for astrophotography will also help capture incredible deep-sky sights.

Editor's Note: If you snap your own photos of comet C/2023 E1 (ATLAS) and would like to share them with Space.com's readers, send your photo(s), comments, and your name and location to spacephotos@space.com.

Dark, billowing clouds sweep across a stunning new view of a large star-forming area of the Orion constellation.

These dense interstellar clouds of gas and dust comprise a dark nebula, formally known as LDN 1622. Dark nebulas are so named because their thick interstellar dust obscures light from nearby stars and other neighboring objects, according to a statement from the U.S. National Science Foundation’s (NSF) NOIRLab. 

LDN 1622 is located 1,300 light-years from Earth in the nearby Orion complex, a star-forming region teeming with young stars. It is located near the plane of our Milky Way galaxy close to the belt and sword of the Orion constellation. 

Related: Spectacular photos of nebulas in deep space

The recent image was taken using the Nicholas U. Mayall 4-meter Telescope at the Kitt Peak National Observatory (KPNO) in Arizona, which is operated by NOIRLab (formally the National Optical-Infrared Astronomy Research Laboratory). 

Astronomers captured this view of LDN 1622 using the telescope’s wide-field camera, called Mosaic-3 — the predecessor of the Mayall scope's Dark Energy Spectroscopic Instrument (DESI), which began operations in 2020 as the most powerful multi-object survey spectrograph in the world, according to the statement. 

"This swap highlights one of the benefits of ground-based astronomy: the ability to upgrade and replace instruments as new technologies become available," NOIRLab officials said in the statement. 

This new image, which NOIRLab shared on June 21, was taken in 2018, before the 2022 Contreras fire that impacted the observatory. The fire, which was caused by a lightning strike, reached the observatory on June 17, 2022. 

While the blaze did not reach any of the observatories’ instruments, it did destroy some non-scientific buildings at the site. DESI is currently operating normally, while the Mosaic-3 instrument has since been retired. 

Follow Samantha Mathewson @Sam_Ashley13. Follow us @Spacedotcom, or on Facebook and Instagram. 

Standing under the night skies in North America pointing out stars with Arabic names and constellations that fit Greek mythology — many derived from Babylonian and Egyptian star knowledge — seems rather odd. After all, indigenous people in North America have been stargazing for many thousands of years.

Full moon names like the 'Hunter's Moon' and 'Wolf Moon' might be familiar to many as ways of various tribes to keep track of the seasons for farming, hunting and gathering, but since there are hundreds of different indigenous tribes in North America, both contemporary and historical, creating a list of official names for anything is perhaps little more than cherry-picking.  

Related: What you can see in tonight's night sky [maps]

Revival of Indigenous astronomy

Indigenous interpretations of the night sky in North America are not only hugely varied across the region, but these oral traditions have suffered over time (though there are plenty of lost constellations in Western astronomy, too). 

However, in recent years there has been a resurgence of interest in, and scholarly work on, indigenous astronomy, most notably the Native Skywatcher's project. Led by native Annette S. Lee, Professor of Astronomy & Physics at St. Cloud State University (SCSU), it seeks to revitalize indigenous astronomy through the resurrection of star maps unique to communities including Ojibwe, D/Lakota and Cree. 

Other resources include Navajo Skies led by Nancy C. Maryboy of the Indigenous Education Institute (IEI) and the free and open-source planetarium software Stellarium, which integrates indigenous sky cultures for the Navajo, Dakota and Ojibwe cultures.

It merely scratches the surface, but here's a tiny sample of just some of the star shapes from indigenous communities in North America to look for in the night sky: 

First Revolving Male, First Revolving Female and Central Fire

Perhaps the most well-known indigenous mythology of the night sky relates to the stars of the north. 

For the Navajo and some other indigenous cultures the Big Dipper, Cassiopeia and — between the two — Polaris, the North Star, are thought of as one huge constellation. The Big Dipper is called Náhookòs Bi'kà' (First Revolving Male), Cassiopeia is Náhookòs Bi'áád (First Revolving Female) and Polaris is Náhookòs Bikò' (the Central Fire). This depiction of a husband and wife around a hearth works well because both constellations are circumpolar so revolve around Polaris. 

However, the Dakota culture sees the Big Dipper as Manka/Maka (Skunk) and its bowl as both To Win (Blue Woman) and Tun Win (Birth Woman). The Ojibwe interpret it as Ojiig (Fisher).

The Wintermaker

The three bright stars that make up the famous Orion's Belt are not only spectacularly aligned but they're surrounded by many other bright stars. 

Many indigenous cultures see Orion as a male figure, just as Greek mythology does — including the Navajo for whom the stars are Átsé Ets'ózí (First Slim One). In Ojibwe culture, the stars Procyon in Canis Minor and Aldebaran in Taurus are added to create a vast figure — Biboonkeonini (The Wintermaker) — so-called because the stars of Orion are best seen in December and the winter months. The Ojibwe and other tribes only tell stories during the winter months when the Wintermaker was visible. 

Curly Tail, The Great Panther

The Ojibwe culture sees Gaadidnaway, Mishi bizhiw (Curly Tail, The Great Panther) while the Greeks saw Leo, the lion. 

It might seem like a similar interpretation, but the two shapes are distinct. The Sickle of Leo, the lion's head — a backward-looking question mark with bright star Regulus as its dot — is instead interpreted by the Anishinabe and Ojibwe cultures as the curly tail of a panther which has its head in the faint stars of the Hydra constellation. In Ojibwe culture, there are four main constellations — The Wintermaker (winter), Curly Tail (spring), Nanaboujou (the stars of Scorpio in summer) and Moose (the stars of Pegasus in fall).

Hole in the Sky

One open cluster of stars, many names. Representing the Seven Sisters in Greek mythology and found in the constellation Taurus, the stars of Pleiades (M45) have dozens of different indigenous names. 

Ojibwe culture calls it the Bugonagiizhig (Hole in the Sky) and it tends to be thought of as a kind of spiritual doorway between Earth and sky while in Dakota, Lakota and Nakota culture it's Wiçinyanna Sakowin/Wiçincala Sakowin (Seven Girls) and the head of the buffalo-like Tayamni constellation. Both cultures also call it Madoo'asinik (Sweating Stones). 

The Navajo call it Dilyéhé and associate it with the planting season. That's because it disappears from the night sky in spring — when seeds need planting — and reappears at harvest time in fall. The other naked-eye open cluster in the northern sky, the Beehive Cluster (M44) in Cancer, is in Navajo culture called Tsetah Dibé (Mountain Sheep). 

First Big One and Man With Feet Apart

Look south after dark in summer from the northern hemisphere and you'll see the stars of Sagittarius, Scorpius, Virgo and Corvus, but in Navajo sky lore there are two figures. Átsé Etsoh (First Big One) sees the upper part of Scorpius as a torso of an elder with a walking stick and a basket. To his left beyond the bright star Spica in Virgo, amid the stars of Corvus, is another figure called Hastiin Sik'aí'ií (Man with Feet Apart).

The Salamander, The Crane and The Skeleton Bird

The Greek constellation of Cygnus, the swan, is sometimes read backward and called the Northern Cross, but in Dakota culture, this same shape — obvious to stargazers across the world during summers throughout history — is called Ahdeska/Agleska (Salamander). To the Ojibwe, it's Ajiijaak (The Crane) — one of the leaders in the Ojibwe clan system — and Bineshi Okanin (The Skeleton Bird). 

The Sacred Hoop

Step outside in January and look south and you'll see the most incredible and enormous shape in the stars around the constellation of Orion. 

There are seven bright blue stars that form a hexagon shape around Orion and the red supergiant star Betelgeuse. The Dakota culture has a variety of names including Çan Hd/Gleska Wakan (Sacred Loop), Inipi/Initipi (Sweat Lodge) and Ki Inyanka Ocanku (Racetrack). 

The pattern is very similar to the Winter Circle or Winter Loop, but with one key difference — instead of Aldebaran as a constituent star, the Pleiades is used. 

Additional resources

If you're curious about Native American constellations and want to learn more of the star lore behind them then be sure to read Nancy C. Maryboy's Navajo Skies, the Native Skywatcher's project, Stars of the First People: Native American Star Myths and Constellations and They Dance in the Sky: Native American Star Myths. 

Bibliography

 A collection of Curricular for the STARLAB Navajo Skies Cylinder, Nancy C. Maryboy, Ph.D. of the Indigenous Education Institue (IEI) https://www.raritanval.edu/sites/default/files/aa_PDF%20Files/6.x%20Community%20Resources/6.4.5_SD.10.NavajoSkies.pdf

Home. Stellarium Labs. (n.d.). https://stellarium-labs.com/

King, B. (2014, November 12). Make way for the Wintermaker. Sky & Telescope. https://skyandtelescope.org/observing/make-way-wintermaker11122014bk/

LeMay, K. (2014, August 13). “native skywatchers” revives Indigenous Star Knowledge. Lake Superior Magazine. https://www.lakesuperior.com/the-lake/natural-world/native-skywatchers-revives-traditional-constellations/

The lost constellations. John C. Barentine’s Personal Website. (n.d.). https://www.johncbarentine.com/the-lost-constellations.html

Minnesota Skies: September 2020. Bell Museum. (2020, August 28). https://www.bellmuseum.umn.edu/blog/minnesota-skies-sept-2020/

Native skywatchers - resources. Native skywatchers. (n.d.). https://www.nativeskywatchers.com/resources.html

Ominika, W. (2020, March 18). Ojibwe astronomy. Great Lakes Guide. https://greatlakes.guide/ideas/ojibwe-astronomy

Star Lore. Myths about the Constellation Orion Part 1. (n.d.). http://judy-volker.com/StarLore/Myths/Orion1.html

The constellation of Orion represents the hunter for most of the year, but in mid-March, this prominent collection of stars becomes hunted by skywatchers. 

The stars of Orion, named after the pinnacle of human excellence in hunting in Homer's epic Greek poem "The Odyssey," can be found shining brightly in the southwestern sky during the evening throughout March. The Orion nebula, the nearest star-forming region to Earth, can be easily found within the constellation and can even be made out with binoculars in reasonably dark skies.

To find Orion, look high in the southern or southwestern skies just after sunset as the stars appear. Throughout the following months, the constellation will begin moving to the west.

Related: Orion Constellation: Facts, location and stars of the hunter

The constellation of Orion is made up of several striking features including the Sword of Orion which descends from Orion's three-starred belt. Both Orion's Sword and Orion's belt are asterisms, loose unofficial patterns of stars that like constellations seem to take the shape of familiar or mythical objects.

The stars that make up Orion's Belt, also known as the Three Kings or the Three Sisters, are the central star Alnilam, a bright supergiant, and Alnitak and Mintaka  —  both of which are actually star systems composed of three and five stars, respectively.

Within Orion's Sword are the stars 42 Orionis and Theta Orionis, the multiple star system Iota Orionis and the bright nebula Messier 42, also known as the Orion Nebula or NGC 1976.

With binoculars, this nebula appears as a fuzzy grayish blob. But the observing power of a even a medium-sized telescope is sufficient to resolve the veils of gas and darker lanes of dust that make up Messier 42. This material forms the building blocks for the new stars being born in this region. 

At the heart of Messier 42 and located around 1,600 light-years from Earth is the Trapezium Cluster or Theta-1 Orionis, a large open cluster of young stars that can be resolved with 5-inch telescopes and larger. The young stars in the Trapezium blast out X-rays and cause the surrounding nebula to glow.

According to MessierObjects.com, the Trapezium Cluster is named after the loose collection of four massive stars that form a trapezoid-shaped asterism at its heart. These stars are designated Theta-1 Orionis A, B, C and D, with Theta-1 Orionis C being the brightest of these at a visual magnitude of 5.13. The star is an incredible 251,000 times more luminous than the sun, making it one of the most luminous stars ever discovered.

Stars Theta-1 Orionis A and B form a binary pairing with the stars eclipsing each other as seen from Earth. Theta-1 Orionis B also happens to be the faintest star in the trapezoid-like asterism. 

The Trapezium Cluster is also believed to play host to a multitude of so-called "failed stars" or brown dwarfs. These are bodies with masses greater than giant planets like Jupiter, but less than stars. This lack of mass means that brown dwarfs aren't able to kick-start the nuclear fusion that defines stars. As a result, they are dim objects meaning spotting them with even a large backyard telescope is unfeasible. 

Something else skywatchers won't be able to see in the Trapezium Cluster even when Orion is visible this March is the intermediate-mass black hole with a mass 100 times that of the sun that scientists proposed in 2012 exists in the cluster.

If you're hoping to catch a look at the constellation of Orion and its stellar occupants, our guides for the best telescopes and best binoculars are a great place to start.

If you're looking to snap photos of Orion or the night sky in general, check out our guide on how to photograph the moon, as well as our best cameras for astrophotography and best lenses for astrophotography.

Editor's Note: If you snap Orion, its stars or the Orion nebula and would like to share it with Space.com's readers, send your photo(s), comments, and your name and location to spacephotos@space.com.

Follow us @Spacedotcom, or on Facebook and Instagram. 

For a few weeks starting on Thursday (March 9), skywatchers have the opportunity to catch a glimpse of a ghostly celestial glowing pyramid of light illuminating the night sky over Earth. 

This phenomenon, known as zodiacal light, is the result of sunlight being reflected by dust particles between the sun and Earth. Catching the zodiacal light will require a bit of planning. It is so faint that it can only be seen in a dark sky that is clear from light pollution both man-made and natural. If you want to find a dark sky site near you, there are plenty of dark sky maps available online. Furthermore, it is only visible for around 90 minutes beginning around 90 minutes after sunset, just after the evening twilight has disappeared in the west. 

Under these circumstances, skywatchers should be able to spot a wedge of light extending from the horizon to the west and following an imaginary eastward line in the sky called the "elliptic" —  the apparent path that the sun traces across Earth's sky. 

Related: Ghostly glow in alien skies: 'Zodiacal light' possibly spotted on 3 exoplanets

The zodiacal light can be followed visually along the ecliptic beginning at around 30 degrees from the sun to about 90 degrees from the star. 

Fortunately, the zodiacal light is visible from Thursday (March 9) until March 21, so there is plenty of time to plan to catch it. Also during this time, two of the brightest planets over Earth, Venus, and Jupiter are in the west after sunset, This means that there is a chance to catch these two worlds framed in this celestial light.

Just as its name implies, the celestial glow of zodiacal light appears in the ring of constellations known as the zodiac also found along the elliptic. But, there's nothing supernatural or "otherworldy" about this glow of course and its manifestation is fairly straightforward to explain. 

Zodiacal light is thought to originate from debris left behind in the solar system from the Jupiter family of comets. These icy bodies are short-period comets with orbits around the sun lasting less than 20 years. They are named after the gas giant because it is the gravitational influence of Jupiter, the largest planet in the solar system, that defines their orbits.

As these comets pass close to the sun, radiation from our star heats them and causes them to shed dust and ice particles which then linger around the sun. This material is commonly seen in the characteristic "tails" that comets grow and the glow that surrounds them, known as the coma. Another source of dust may be collisions between asteroids located in the asteroid belt between Jupiter and Mars. 

These dust grains spread around the sun in a flat disk shape that spirals slowly around the star. It shares the same plane as the inner planets: Mercury, Venus, Earth, and Mars. Ranging from around a millimeter to a micron (one ten-thousandth of a centimeter), these particles reflect sunlight that falls on them, creating the zodiacal glow.

If you miss the zodiacal light in these spring evenings, the autumn months over another opportunity to catch it in the Northern Hemisphere. This will require heading out to an area with dark skies before sunrise as this pyramid of light is best seen before dawn from late August to early November. 

If you're hoping to catch a look at the zodiacal light glow, our guide for the best binoculars are a great place to start. Low magnification wide-angle binoculars could be a great tool for seeing zodiacal light. If you want to zoom in on smaller objects in the night sky, check out our guide for the best telescopes. 

And if you're looking to snap photos of this phenomenon of the night sky in general, check out our guide on how to photograph the moon, as well as our best cameras for astrophotography and best lenses for astrophotography.

Editor's Note: If you snap the zodiacal light and would like to share it with Space.com's readers, send your photo(s), comments, and your name and location to spacephotos@space.com. 

Follow us @Spacedotcom, or on Facebook and Instagram. 

Ursa Major, also known as the Great Bear, is the third-largest constellation in the sky and the largest constellation in the Northern Hemisphere. 

It includes the Big Dipper asterism and is one of the most recognizable collections of stars in the Northern Hemisphere. 

We explore this infamous constellation in more detail and explore objects near the stars of Ursa Major that could make for an interesting skywatching target.

Related: Constellations of the western zodiac

Ursa Major FAQs answered by an expert

We asked Mindy Townsend, Dudley Astronomer at Siena College in upstate New York a few commonly asked questions about Ursa Major.  

Where is Ursa Major?

The constellation Ursa Major can be seen in its entirety from the Northern Hemisphere, in the second stellar quadrant. According to constellation-guide.com, over the course of a year, Ursa Major looks as if it were rotating around the north celestial pole, or the star Polaris. 

Viewers in the Northern Hemisphere should look generally north to see the constellation, which skywatchers can spot most easily by looking for the Big Dipper (also known as the Plough, among other names).  

Ursa Major observing targets

Astronomers have identified several other objects of interest near the stars of Ursa Major. For the best view of these objects, we recommend using binoculars or a telescope. If you need equipment, our best binoculars and best telescopes guides may help. 

To find the objects of interest, it's helpful to know their magnitude, right ascension (RA) and declination (Dec).  

Magnitude tells you how bright an object appears from Earth. The lower the magnitude, the brighter the object. For example, an object with a magnitude of -1 is brighter than one with a magnitude of +2. 

Right ascension is to the sky what longitude is to the surface of Earth, corresponding to east and west directions. It's measured in hours, minutes and seconds. 

Declination tells you how high an object will rise in the sky. Like Earth's latitude, declination measures north and south. Its units are degrees, arc minutes and arc seconds. There are 60 arc minutes in a degree and 60 arc seconds in an arc minute.  

Bode's Galaxy (Messier 81) 

Bode's Galaxy is among the brightest galaxies in the night sky. According to NASA, it was first discovered by German astronomer Johann Elert Bode in 1774 and was later reclassified by French astronomer Charles Messier in 1781. While the galaxy's arms are made up of mostly young blue stars formed in the past 600 million years, its center consists of older red stars and a black hole about 15 times more massive than the black hole at the center of the Milky Way. 

Cigar Galaxy (Messier 82) 

The Cigar Galaxy is near Bode's Galaxy; the two galaxies are likely visible in the same telescope, depending on its field of view. The Cigar Galaxy is remarkable for its star formation activity, with an extraordinary rate of star formation swelling its numbers in what NASA calls a "starburst." Eventually, the galaxy will run out of material and the starburst will subside. But for now, near the center of the galaxy, young stars are being born 10 times faster than in the Milky Way.  

Pinwheel Galaxy (Messier 101)  

The gigantic Pinwheel Galaxy contains at least 1 trillion stars, NASA estimates. The galaxy's spiral disk stretches 170,000 light-years across; for comparison, the Milky Way's vast collection of stars, gas clouds and dust is 105,700 light-years in diameter. 

I Zwicky 18 

The galaxy I Zwicky 18 was once thought to be the youngest galaxy ever observed, possibly forming as recently as 500 million years ago. But later research showed that it contained some very old stars and likely formed around the same time as other galaxies. According to the European Space Agency, astronomers now think that instead of being particularly youthful, the galaxy has had a notably slow rate of star formation, and they're not sure why.  

Hubble Deep Field 

The first Hubble Deep Field is an area of space in the Ursa Major constellation, chosen because it appears relatively empty. In 1995, the Hubble Space Telescope took 342 images of the area, taking advantage of its "emptiness" to see farther away — and thus further back in time — than any telescope had before. In the end, according to NASA, the telescope imaged over 3,000 young galaxies too distant to be detected by other telescopes. 

Ursa Major in world culture

The stars that make up the constellation Ursa Major were described as a "great bear" by ancient Greek astronomer Claudius Ptolemy in his classic studies of the night sky, and Greek myths tell the story of a nymph named Callisto who was transformed into a bear and hidden in the stars by Zeus, according to GreekMythology.com. 

But the same stars have also been described and used for storytelling or navigation by many other groups and cultures. For example, according to the Swinburne University of Technology, Ursa Major was known to ancient Egyptians as an ox and ox handler, depicted in paintings found in the tomb of the pharaoh Seti I. And in ancient Chinese astronomy, the constellation depicts a celestial bureaucrat carried on a cloud. 

The Mi'kmaq people, whose traditional lands are in the northeastern part of North America, also describe the stars in Ursa Major as a great bear (or Mother Bear, depending on the translation) and the hunters that pursued her, according to Digital Museums Canada. Other Native American peoples saw the same stars as loons, a canoe, wolves, bison, elk or caribou, according to Western Washington University. 

Today, the stars in Ursa Major feature in Polynesian wayfinding, according to the Polynesian Voyaging Society. They are part of a group of stars called "The Seven," featured in master navigator Nainoa Thompson's second star line.

Additional resources

For kids and anyone who likes to get crafty, try this mobile-building activity from the American Museum of Natural History to see the stars of Ursa Major from all angles. Then, check out the rest of the galaxy with the Milky Way Explorer. If you want more stories about the constellations and their myths, read Ian Ridpath's "Star Tales" (Lutterworth Press, 1989). 

Bibliography

Belleville, M. (2023, January 13). Discoveries — Hubble's deep fields. NASA. http://www.nasa.gov/content/discoveries-hubbles-deep-fields 

Constellation Guide. (n.d.). Northern constellations. Retrieved February 14, 2023, from https://www.constellation-guide.com/constellation-map/northern-constellations/

Constellation Guide. (n.d.). Ursa major constellation: Stars, myth, facts, location. Retrieved February 14, 2023, from https://www.constellation-guide.com/constellation-list/ursa-major-constellation/ 

Digital Museums Canada. (n.d.). The Amerindian sky. Canada Under the Stars. Retrieved February 14, 2023, from http://astro-canada.ca/le_ciel_des_amerindiens-the_amerindian_sky-eng 

European Space Agency. (2007, October 16). Hubble shows 'baby' galaxy is not so young after all. https://www.spacetelescope.org/news/heic0716/ 

Garner, R. (2017, October 19). Messier 81. NASA. http://www.nasa.gov/feature/goddard/2017/messier-81 

Garner, R. (2017, October 19). Messier 82 (The cigar galaxy). NASA. http://www.nasa.gov/feature/goddard/2017/messier-82-the-cigar-galaxy 

Garner, R. (2017, October 19). Messier 101 (The pinwheel galaxy). NASA. http://www.nasa.gov/feature/goddard/2017/messier-101-the-pinwheel-galaxy 

GreekMythology.com. (2015, January 31). Callisto. https://www.greekmythology.com/Myths/The_Myths/Zeus's_Lovers/Callisto/callisto.html 

Polynesian Wayfinding Society. (n.d.). Hawaiian Star Lines. Retrieved February 14, 2023, from https://www.hokulea.com/education-at-sea/polynesian-navigation/polynesian-non-instrument-wayfinding/hawaiian-star-lines/ 

Swinburne University of Technology. (n.d.). Constellation. Retrieved February 15, 2023, from https://astronomy.swin.edu.au/cosmos/c/Constellation 

Western Washington University. (2022, March 2). Native American sky. https://www.wwu.edu/astro101/indiansky.shtml 

Shining down upon us all winter long, Orion is the brightest and grandest of all the constellations. 

Dominating our winter evening skies is the Great Hunter or Celestial Warrior the most brilliant of the constellations and visible from every inhabited part of the Earth. This season, Orion can readily be found standing high in the southern sky at nightfall and doesn't completely set until around 1:30 a.m. Throughout March, the Hunter will begin to move westward. Three bright stars in a diagonal line in the middle of a bright rectangle decorate Orion's belt which points northward to the bright orange star Aldebaran of Taurus, and southward to the Dog Star, Sirius.

Within Orion we find two immense stars, Rigel and Betelgeuse, apparently at two entirely different periods in a star's existence. In Rigel (the "Left Leg of the Giant"), we find a star apparently reaching the prime of its life. Betelgeuse ("The Armpit of the Giant") in contrast, shines with a cool, dull ruddy hue; an irregular pulsating supergiant star, nearing the end of its life and as such it expands and contracts spasmodically. 

Read more: Orion Constellation: Facts, location and stars of the hunter

Alluring cloud of gas and dust

But undoubtedly one of the most wonderfully beautiful objects in the night sky is the Great Orion Nebula, also known as M42. It appears to surround the middle star of the three stars that lie below the Hunter's belt between its 'legs.' 

Plainly visible to the naked eye under a dark sky, it can be clearly resolved in good binoculars and small telescopes — even from urban areas — as a bright gray-green mist enveloping the star. 

In larger telescopes it appears as a great glowing irregular cloud; there is considerable detail with branches, rifts and rays. A sort of auroral glow is induced in this nebula by fluorescence from the strong ultraviolet radiation of four hot stars called the "Trapezium," entangled within it. In 1929, amateur astronomer, William T. Olcott wrote: "Words fail utterly to describe its beauty." 

The Great Orion Nebula is a vast cloud of extremely tenuous glowing gas and dust, approximately 1,600 light-years away and about 30 light-years across (or more than 20,000 times the diameter of the entire solar system). Astrophysicists now believe that this nebulous stuff is a stellar incubator; the primeval chaos from which star formation is presently underway.

Painting outdoes photograph

Everyone who has viewed M42 agrees that no photograph they had seen compared in splendor to what appeared in the eyepiece. Its complex, gossamer-like structure is indeed an eyeful, but photographs often "burn-out" the inner region of the nebula and obscure the Trapezium stars. In 1880, using M42 as his subject, Henry Draper (1837-1882), known as a pioneer of astrophotography, was the first person to successfully photograph a nebula. 

In 1875, during his stay at Harvard Observatory, French artist and astronomer Étienne Léopold Trouvelot (1827-1895) captured almost to perfection, the remarkable detail of the Great Orion Nebula. Interestingly, he didn't draw it merely by "eyeballing." Instead, Trouvelot used a grid of squares in the eyepiece and then meticulously copied the details onto squared paper. In addition, there are many other sky objects which he depicted such as solar eclipses, comets and the Milky Way, which made him known worldwide as one of the finest artists of celestial objects during the late 19th century.

But these beautiful renditions were not the only legacy that Trouvelot brought to our shores. 

If you want to check out the Orion nebula for yourself, our guides for the best telescopes and best binoculars are a great place to start. It doesn't take much to be able to see many of the deep space wonders of the night sky!

And if you're looking to snap your own gorgeous photos of the night sky, check out our guide on how to photograph the moon, as well as our best cameras for astrophotography and best lenses for astrophotography.

A scorned legacy

Besides being an astronomer and artist, Trouvelot was also an amateur entomologist. In 1869 he had a wild idea to produce silk more cheaply by crossing the silkworm with the spongy moth. 

You might know the latter insect better by its former name, the gypsy moth, but in March 2022, The Entomological Society of America formally adopted the new name, spongy moth. This change was necessary because the word 'gypsy' is considered a derogatory term for the Romani people. The moth's new moniker, is derived from the common name used in France and French-speaking Canada, "spongieuse," and refers to the moth's sponge-like egg masses.

So Trouvelot imported some live egg clusters to his home in Medford, Massachusetts for experimentation. He failed, but some of the creatures escaped and after a decade began to proliferate alarmingly; over the next century, spreading throughout New England, the Mid-Atlantic, Greater Ohio Valley, Piedmont and southern Great Lakes, to the point where late-spring infestations periodically cover forests and houses with hairy caterpillars that denude oak tree foliage as they produce their "silk." 

I saw this firsthand several years ago when my own property endured an invasion of spongy moths and as a consequence, I lost several majestic hardwood trees. Today this pest is listed as one of the 100 most destructive invasive species worldwide.

No question about it. Trouvelot should have stuck to astronomy! 

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, the Farmers' Almanac and other publications. Follow us on Twitter @Spacedotcom and on Facebook. 

Shiny clouds lingered in the Florida sky in the hours after SpaceX launched its latest mission from the Space Coast early Thursday morning (Jan. 26).

SpaceX launched 56 Starlink satellites from Cape Canaveral Space Force Station in Florida at 4:32 a.m. EST (0932 GMT). The predawn launch produced noctilucent clouds that were visible after the launch, according to local reports posted on Twitter.

"These never get old and are different after every launch," posted meteorologist Wright Dobbs, who viewed the clouds from Tallahassee, a four-hour drive away from the launch site, which is near Orlando.

Noctilucent clouds are rare high-altitude clouds that can also appear naturally, but only when specific conditions are fulfilled. In general they are visible in the summer months, after sunset, and are distinctive wispy streaks that stand out from other cloud types. 

Related: SpaceX's Starlink megaconstellation launches in photos

It's common for SpaceX launches to leave behind intriguing sky patterns, including  "space jellyfish" or spiral shapes high in the sky. These are harmless effects resulting from rocket gases high in the atmosphere.

SpaceX has launched six times this year so far and could get to 100 liftoffs overall in 2023 across its various programs, including launches to the International Space Station with astronauts on board, as well as forthcoming opportunities with the Falcon 9, Falcon Heavy and potentially the giant Starship Mars rocket, which is still in development.

Editor's note: If you captured a stunning view of the SpaceX launch and want to share it for an image gallery or story, let us know! You can send images and comments in to spacephotos@space.com.

Follow Elizabeth Howell on Twitter @howellspace. Follow us on Twitter @Spacedotcom or Facebook. 

Artificial light pollution from Earth is contaminating the skies over most major astronomical observatories, requiring immediate action to remedy, a team of international scientists has determined.

The team, including scientists from Italy, Chile and Spain, compared light pollution at almost 50 observatories, ranging from some of the largest professional observatories in the world to smaller amateur-focused facilities. The scientists then applied a model of how light travels through Earth's atmosphere to night views taken by satellites. 

The researchers also accounted for light pollution across the entire night sky. Directly overhead, or the zenith, is less polluted by light and is therefore the darkest portion of the night sky, but the researchers also measured the average brightness at altitudes of 30 degrees — the lowest that a telescope at a ground-based observatory can point — as well as for the first 10 degrees above the horizon. The scientists also considered the overall average brightness across the sky and how artificial light coming from the night sky illuminated the ground.

Related: How dark is your night sky? An observer's guide

The scientists then compared these measurements with light originating from stars and the Milky Way, as well as the natural sky brightness provided by the faint emission of light by Earth's atmosphere called "airglow." 

With all these factors combined, the researchers were able to model how artificial light affects the night sky and determined that the night sky over major observatories is more polluted by light than previously assumed. 

The team found that only seven of 28 major observatories, defined as a facility with a telescope of a diameter of 10 feet (3 meters) or more, had a zenith brightness with light below the expected natural sky brightness threshold of 1%. The researchers considered anything above this threshold "contaminated" and anything below it "uncontaminated," so only seven major sites were considered contaminated by no more than the natural level of sky brightness. 

Even worse, only one of the 28 major sites examined by the scientists had light pollution below the 1% threshold at 30 degrees above the horizon. The researchers also considered a higher maximum allowable artificial brightness threshold for major observatories of 10% set by the International Astronomical Union in the 1970s, but still two-thirds of major ground-based observatories exceeded this more lenient limit. 

The least contaminated of all the sites featured in the study was a lodge in Namibia that houses several telescopes rented to amateur astronomers, according to Fabio Falchi, a physicist specializing in light pollution at the Universidade de Santiago de Compostela in Spain and lead author on the new research.

"I was recently there and I can confirm that it is the least light-polluted site I've ever seen," he said in a statement. "We must try to decrease the light pollution levels at other sites in order to protect the future of ground-based astronomy."

The team's research is described in a paper published Tuesday (Dec. 20) in the journal Monthly Notices of the Royal Astronomical Society.

Follow us on Twitter @Spacedotcom or on Facebook. 

The Southern Cross is an asterism made up of the most visible stars in the constellation Crux. 

The iconic group of stars is visible mainly from the Southern Hemisphere. Because of its orientation in the night sky, the Southern Cross has historically served as an essential navigational guide: two of its major stars form a line that points to the South Pole. The Southern Cross is also featured in the flags of several Southern Hemisphere countries.

Crux is the smallest of the 88 official constellations defined by the International Astronomical Union (IAU). The Southern Cross is not the entire region of the sky that makes up Crux, but rather just the four (or five) stars that make its iconic cross shape: That's what makes it an asterism. 

Related: How many stars are in the universe?

What stars are in the Southern Cross?

The Southern Cross is made up of four or five stars, depending on who you ask. The four main stars, according to Constellation Guide, are Acrux (also known as Alpha Crucis), Mimosa (Beta Crucis), Gacrux (Gamma Crucis) and Imai (Delta Crucis). Acrux is the southernmost star, while Gacrux is the farthest north. Mimosa and Imai form the crossbeam.

The fifth brightest star in the Crux constellation, Ginan (Epsilon Crucis), is included in some depictions of the Southern Cross: for example, the national flags of Australia, Papua New Guinea, Samoa and Brazil. Ginan appears in the space between Imai and Acrux, not as part of the main cross formation. It's left off of the national flag of New Zealand, which features only the four brightest stars of the cross.

Alpha, beta and delta Crucius — also known as Acrux, Mimosa and Imai — likely share a common origin, wrote Constellation Guide, as they are all made up of massive, hot-burning B-type stars. 

Acrux, the brightest and southernmost star in the Southern Cross, is the 13th-brightest star in the night sky with a visual magnitude of +.76, according to a 1966 paper published in the journal Monthly Notes of the Astronomical Society of Southern Africa. The lower a star's visual magnitude is, the brighter that star is. For comparison, the brightest star in Earth's sky is Sirius, with a magnitude of -1.46. 

While for magnitude purposes it is considered to be one star, Acrux is actually a multiple star system, according to the Astronomical Society of Southern Africa. While it looks like one star to an unassisted observer on Earth, more sensitive telescopes reveal that it is made up of several components.

What else can you see in the Southern Cross?

Astronomers have identified several other objects of interest in or near the Southern Cross. For the best view of these objects, we recommend using binoculars or a telescope. If you need equipment, our best binoculars and best telescopes guides may help. 

In order to find the planetary nebulae, it's helpful to know their magnitude, right ascension (RA) and declination (Dec). 

Magnitude tells you how bright an object is as it appears from the Earth. The lower the number of an object's magnitude, the brighter the object. For example, an object of a -1 magnitude is brighter than one with a magnitude of +2. 

Right ascension is to the sky what longitude is to the surface of the Earth, corresponding to east and west directions. It's measured in hours, minutes and seconds. 

Declination tells you how high an object will rise in the sky. Like Earth's latitude, declination measures north and south. Its units are degrees, arcminutes and arcseconds. There are 60 arcmins in a degree and 60 arcsecs in an arcmin. 

The Coalsack Nebula 

The Coalsack Nebula according to the European Southern Observatory (ESO) forms a conspicuous dark silhouette against the Milky Way. The nebula, wrote the ESO, has been recognizable to people in the southern hemisphere for "as long as our species has existed." That's because it is one of the most prominent objects of its kind visible to the unaided eye — an inky blotch in an otherwise bright area at night. Millions of years from now, the ESO wrote, the Coalsack will end this dark phase and ignite with new stars, flammable just like the dark coal it's named after.

The Jewel Box 

Another object of interest in the Southern Cross is the Jewel Box, a galactic star cluster located about 6400 light-years away. According to the European Space Agency (ESA) it is approximately 16 million years old, and is just bright enough to be seen with the naked eye. Its nickname dates back to the 1830s and comes from the English astronomer John Herschel (son of astronomer William Herschel), the ESA wrote, because its twinkling blue and orange stars made Herschel think of a piece of exotic jewelry. 

How can you find Southern Cross?

According to the IAU, Crux is the smallest of the 88 officially recognized constellations. But it's still easy to spot for viewers in the Southern Hemisphere, especially those more than 35 degrees south where the stars are visible any time of night, all year round. It's even visible some times of year for those in the Northern Hemisphere below about 26 degrees, wrote EarthSky. Hawaii, southern Florida, and some parts of Texas, for example, will see the stars of the cross clear the horizon on clear May evenings. 

To spot the Southern Cross, viewers use two "pointer stars," Alpha Centauri and Beta Centauri, wrote The Australian Broadcasting Corporation (the ABC). That's in part how skywatchers can separate the true Southern Cross from a number of false crosses in the night sky. 

From the Northern Hemisphere, the cross will generally appear vertical. But in the Southern Hemisphere, according to the ABC, the cross could appear to be lying on its side or upside down depending on the month and the time of night. 

The easiest way to make sure you're looking at the right Southern Cross is to use a compass. Look south, follow the Milky Way, and draw a line between the bright pointer stars to find the cross.

How is the Southern Cross used for navigation?

The Southern Cross can be used to point a navigator on the Earth's surface toward the celestial south pole, according to EarthSky. A line drawn from Gacrux at the top of the cross through Acrux at the bottom will point to the south. 

Navigators using traditional Polynesian wayfinding techniques also use the stars of the Southern Cross as one of many pointers to the south, according to the Polynesian Voyaging Society. 

The cultural significance of the Southern Cross

The Southern Cross asterism appears in multiple national flags, as noted above. The stars were valuable guides to European explorers who left the stars they knew — Polaris and the Big Dipper, for example — to navigate seas in the Southern Hemisphere. The first European to describe the five stars of the Southern Cross, Andrea Corsali, wrote of their beauty and behavior in 1515 for his patrons in the Medici family, according to a 2019 article from Hordern House. Corsali's description provided a resource for centuries of later European explorers.

But the stars were first known by civilizations that far predated the European seafarers: for example, the ABC lists several myths from Indigenous peoples of Australia identifying the stars as part of a wedge-tailed eagle, an emu's head, or a group of trouble-making youngsters. In fact, the IAU recognizes the star Ginan by the name given to it thousands of years ago by the Wardaman people of northern Australia, according to a news article in the Sydney Morning Herald. The Indigenous Knowledge Institute at the University of Melbourne notes that Indigenous Australians used the Southern Cross stars to navigate.

The Maori, the Indigenous people of New Zealand, also named and referred to the stars identified by the IAU as the Southern Cross. The Maori considered the asterism to be the anchor of a celestial canoe, according to Te Aka, a Maori language dictionary. 

Incan astronomers associated the same area of the sky with the tinamou, a ground-dwelling, seed-eating bird. In a 1981 paper in the Proceedings of the American Philosophical Society, the author speculates that while the stars of the Southern Cross rose in the sky each year, tinamous likely thrived on the arrival of the rainy season. The cycle of those stars corresponded with the time in which farmers would have been planting their vulnerable seed. 

Additional resources

For more on the Southern Cross and traditional Polynesian wayfinding, watch this video of navigator Nainoa Thomson talking about those stars. And to get another insight into why people choose particular stars as constellations and asterisms, check out this article from Science News Explores.  

Bibliography

Annab, R. (2020, May 28). Stellar navigation and mathematics. Indigenous Knowledge Institute. https://indigenousknowledge.unimelb.edu.au/curriculum/resources/stellar-navigation-and-mathematics

Blane, D. (2014, February 24). Alpha crucis — double star of the month. ASSA. http://assa.saao.ac.za/sections/double-and-variable-stars/double-stars/news-and-articles/alpha-crucis-double-star-of-the-month/

Corben, P. M. (1966). Photoelectric magnitudes and colours for bright southern stars. Monthly Notes of the Astronomical Society of South Africa, 25, 44. https://ui.adsabs.harvard.edu/abs/1966MNSSA..25...44C

Duarte, P. A. (2008, May 2). Astronomia da bandeira brasileira. Departamento de Geociências da Universidade Federal de Santa Catarina. https://web.archive.org/web/20080502120005/http://www.cfh.ufsc.br/~planetar/textos/astroban.htm

Hook, R. (2015, October 14). A cosmic sackful of black coal—Part of the coalsack nebula in close-up. Www.Eso.Org; European Southern Observatory. https://www.eso.org/public/news/eso1539/

Lomb, N. (2008, July 21). Finding south using the Southern Cross — an essential skill. Observations. https://www.maas.museum/observations/2008/07/21/finding-south-using-the-southern-cross-an-essential-skill/

Mannix, L. (2018, January 16). Southern Cross star given new name to recognise Aboriginal astronomy. The Sydney Morning Herald. https://www.smh.com.au/technology/southern-cross-star-renamed-to-recognise-aboriginal-astronomy-20180116-h0j1yf.html

McClure, B. (2021, April 1). How to see the southern cross from the northern hemisphere | favorite star patterns | earthsky. EarthSky.org. https://earthsky.org/favorite-star-patterns/the-southern-cross-signpost-of-southern-skies/

Meridian pointers to south. Hōkūleʻa. Retrieved October 29, 2022, from https://www.hokulea.com/education-at-sea/polynesian-navigation/polynesian-non-instrument-wayfinding/meridian-pointers-to-south/

Sharkey, C. (2009, October 29). Opening up a colourful cosmic Jewel Box. Www.Spacetelescope.Org; European Space Agency. https://www.spacetelescope.org/news/heic0913/

Southern cross: Guide to south celestial pole — constellation guide. (n.d.). Retrieved October 29, 2022, from https://www.constellation-guide.com/the-southern-cross/

The Constellations. The International Astronomical Union; IAU. Retrieved October 27, 2022, from https://www.iau.org/public/themes/constellations/

Virtual tours » beginner's guide to the night sky(Abc science). (2019). Australian Broadcasting Corporation. https://www.abc.net.au/science/starhunt/tour/virtual/

Waka o tamarēreti, te—Te aka māori dictionary. Waka o Tamarēreti, Te - Te Aka Māori Dictionary. Retrieved October 29, 2022, from https://www.maoridictionary.co.nz/

Aquarius is a constellation in the Western Zodiac and one of 88 official constellations according to the International Astronomical Union (IAU). The constellation describes a large group of stars that ancient Greek astronomers saw as a picture in the night sky. Aquarius was said to represent a "cup bearer" or "water bearer," which is what its name means in Latin. 

Aquarius is one of the oldest constellations documented in the historical record, first recorded in the second century by the Greek astronomer Claudius Ptolemy. 

Now, scientists and skywatchers look to Aquarius to find Earth-like planets in the Trappist-1 system, and to catalog the stars, meteor showers and other astronomical objects associated with that region of the sky. 

Related: How many stars are in the universe? 

Where is the Aquarius constellation?

Aquarius is the 10th largest constellation in the sky according to astronomy writer Ian Ridpath. But there are no particularly bright stars in the constellation and it can be difficult to view with the naked eye. Even so, it covers about 980 square degrees and takes up more than two percent of the night sky when visible. 

The constellation can be seen in the spring in the Southern Hemisphere and the fall in the Northern Hemisphere.

 Aquarius is located near other water-related constellations: Cetus (the whale), Pisces (the fish), Delphinus (the dolphin) and Eridanus (the river). This area is often referred to as the water or sea section of the sky, according to EarthSky. 

What stars make up Aquarius?

The brightest star in the Aquarius constellation, according to Star Facts, is a rare yellow supergiant known as beta Aquarii, also known as Sadalsuud. While its mass is just five times that of the sun, its volume is close to 50 times the sun's volume, according to a 2017 paper from The Astronomical Journal. The star has a magnitude of 2.87, according to a 1966 paper published in the journal Communications of the Lunar and Planetary Laboratory, which means it appears relatively dim in our sky. It is nearly 600 light-years from our sun.

Alpha Aquarii, or Sadalmelik, is also a yellow supergiant star, writes the astronomy website Star Facts. It is located around 520 light-years from the sun and has a magnitude of 2.95. 

Gamma Aquarii, or Sadachbia, has a magnitude of 3.8 according to Constellation Guide. Zeta Aquarii is at the center of the Y-shaped configuration that forms Aquarius' water jar. The other stars in the asterism forming the jar are gamma, phi and eta Aquarii. The "stream of water" pouring from the jar consists of more than 20 stars, ending with the star Fomalhaut. 

Aquarius observing targets

Aquarius includes several planetary nebulas. For the best view of these objects, we recommend using binoculars or a telescope. If you need equipment, our best binoculars and best telescopes guides may help. 

In order to find the planetary nebulae, it’s helpful to know their magnitude, right ascension (RA) and declination (Dec). 

Magnitude tells you how bright an object is as it appears from the Earth. The lower the number of an object’s magnitude, the brighter the object. For example, an object of a -1 magnitude is brighter than one with a magnitude of +2. 

Right ascension is to the sky what longitude is to the surface of the Earth, corresponding to east and west directions. It’s measured in hours, minutes and seconds. 

Declination tells you how high an object will rise in the sky. Like Earth's latitude, declination measures north and south. Its units are degrees, arcminutes and arcseconds. There are 60 arcmins in a degree and 60 arcsecs in an arcmin.

Saturn Nebula 

NGC 7009 is one of the brightest planetary nebulae in the sky, and can be found in the Aquarius constellation. NGC 7009 is also known as the Saturn Nebula, for the cloud of dust and hot gas that blew out from a dying star and formed the approximate shape of the planet Saturn. (Planetary nebulas were so named because early observers mistook them for planets, even though they are not planets at all.) 

According to the ESO, the Saturn Nebula tells a story about the lives and deaths of low mass stars to astronomers using the Multi Unit Spectroscopic Explorer (MUSE) tool on the ESO’s Very Large Telescope. The Saturn Nebula was first observed in 1782 by Sir William Herschel, a German-born British astronomer. 

Helix Nebula

Aquarius also boasts one of the closest of all planetary nebulae — NGC 7293, or the Helix Nebula — which is less than 700 light-years from Earth. Like many planetary nebulae, the Helix Nebula emits waves across a broad swath of the spectrum, from ultraviolet to infrared, and appears similar when viewed in each wavelength. According to NASA, that’s one of the most intriguing features of this type of object.  

What are scientists looking for in Aquarius?

Aquarius hosts the ultracool star TRAPPIST-1, which is only 40 light-years from Earth (about 10 times the distance from our planet to the nearest star system, Alpha Centauri.) In 2017, astronomers announced that the star hosts at least seven exoplanets, all Earth-sized worlds that are likely also rocky. Many of these planets orbit in the habitable region of the star — the zone in which water could potentially exist on the planets' surfaces.

 Planets were first discovered around this star using Chile's Transiting Planets and Planetesimals Small Telescope (TRAPPIST), in 2010. Follow-up observations have been performed with observatories such as the Very Large Telescope (VLT) in Chile and NASA's Spitzer Space Telescope, but astronomers say a more detailed look may need to wait until NASA's James Webb Space Telescope can examine the system.

Related: The 10 most Earth-like exoplanets

Aquarius mythology

In astrology, which is not a science, Aquarius is the 11th sign in the Zodiac and represents those born between Jan. 20 and Feb. 18.

The Greeks linked this constellation with Ganymede, the cupbearer to the gods, or with Zeus pouring life-giving water on the Earth, wrote NASA's Chandra X-Ray Observatory.

 Because the rising of Aquarius coincided with the rainy season in the Northern Hemisphere, many other cultures also associated these stars with water. For example, wrote the observatory, Arabic astronomers identified the same constellation as a "well-bucket" and named many of its stars to include the word "luck," possibly because seasonal rains were considered good fortune. Chinese, Indian, and Babylonian astronomers also constructed water-related myths around these stars.

Related: What's your zodiac sign? (It may not be what you think it is)

Additional resources

For an especially kid-friendly explanation of constellations, check out NASA's Space Place page. If you're interested in the history of the Western Zodiac, read this article from Time Magazine. And for a book on the constellations — and the science related to the exploration of each one — take a dive into Constellations: the Story of Space Told Through the 88 Known Star Patterns in the Night Sky (Black Dog & Leventhal, 2019) by Govert Schilling. 

Bibliography

Admin. (2021, January 25). Sadalsuud (Beta aquarii) — star facts. https://www.star-facts.com/sadalsuud/

Aquarius constellation: Stars, myth, facts, location, deep sky objects — constellation guide. Retrieved October 28, 2022, from https://www.constellation-guide.com/constellation-list/aquarius-constellation/

Aquarius constellation—Features and facts. The Planets. Retrieved October 28, 2022, from https://theplanets.org/constellations/aquarius-constellation/

Aquarius: The Water-Bearer. Chandra X-Ray Observatory; NASA. Retrieved October 28, 2022, from https://chandra.harvard.edu/photo/constellations/aquarius.html

Baines, E. K., Armstrong, J. T., Schmitt, H. R., Zavala, R. T., Benson, J. A., Hutter, D. J., Tycner, C., & Belle, G. T. van. (2017). Fundamental parameters of 87 stars from the navy precision optical interferometer. The Astronomical Journal, 155(1), 30. https://doi.org/10.3847/1538-3881/aa9d8b

Johnson, H. L., Mitchell, R. I., Iriarte, B., & Wisniewski, W. Z. (1966). Ubvrijkl photometry of the bright stars. Communications of the Lunar and Planetary Laboratory, 4, 99–110. https://ui.adsabs.harvard.edu/abs/1966CoLPL...4...99J

McLure, B. (2022, October 16). Meet Aquarius the Water Bearer and its Stars. EarthSky. https://earthsky.org/constellations/aquarius-heres-your-constellation/

Ridpath, I. The Constellations. Ian Ridpath. Retrieved October 27, 2022, from http://www.ianridpath.com/constellations1.html

The Constellations. The International Astronomical Union; IAU. Retrieved October 27, 2022, from https://www.iau.org/public/themes/constellations/

As the Earth completes one turn on its axis every 23 hours and 56 minutes, the sky seems to wheel overhead. To sky watchers in the north temperate zone, the stars that are near to the north celestial pole constantly remain in view as they sweep around, while stars near to the celestial equator appear to rise and set. 

Several star patterns are arranged around the pole and not very far from it. These are the circumpolar constellations. They can appear high or low in the sky as they wheel around the North Star (Polaris) but they never rise or set and can be seen anytime of the year. As viewed from latitude 40-degrees north Ursa Minor, Cassiopeia, Cepheus, Draco and Camelopardalis are constellations that fall into this category. 

However, the two most conspicuous constellations whirling in their nightly course in the northern skies are the Big Dipper and the "W" of Cassiopeia the Queen, and Friday evening (Oct. 14) is a perfect time to see these two.

Related: Night sky, October 2022: What you can see tonight [maps]

One of the most famous constellations is the Big Dipper, a very popular star pattern (known in Great Britain as "The Plough") which falls into the category of an asterism — not an official constellation in of itself, but a prominent part of the constellation of Ursa Major, the Great Bear. The star located at the end of the Dipper's handle (Alkaid) briefly drops just below the northern horizon from latitude 40 degrees north for 66 minutes each day, so the Big Dipper cannot be considered circumpolar for Philadelphia. 

But for New York City, located 80 miles (130 km) to the northeast, Alkaid appears to barely skim the horizon but never drops below it. So, for New Yorkers the Big Dipper is circumpolar. 

At this particular time of the year, the Dipper and its associated constellation of the Great Bear is at its nadir — that is, its lowest point in the sky during the late-evening hours (9 to 11 p.m.). In contrast, Cassiopeia soars some three-quarters up from the northern horizon to the point directly overhead (the zenith). 

So, in our current early autumn sky, the Whirling Queen rides high, while the Dipper dips down low. 

Let's check both out, starting with the "Big W" in the sky. 

High Flying Queen

The striking W-shaped figure of Cassiopeia is on the other side of Polaris from the Big Dipper. All through the night and every night throughout the year she looks down upon us whenever the sky is clear. In Greek mythology, she was Queen of the ancient kingdom of Ethiopia — wife of King Cepheus and mother of the Princess Andromeda. 

In Roman legend, Cassiopeia was chained to her throne, as a punishment for her boastfulness and placed in the heavens to sometimes hang upside-down. Arab cultures pictured the zig-zag row of five bright twinklers as representing a kneeling camel. Along with resembling a "W", these stars can also be looked upon as forming an irregular letter "M", depending on which way the figure is turned in its circling around the pole. An additional fainter star can be added to the five main stars, so that the six together outlines Cassiopeia's Chair. 

At this time of the year as darkness falls, Cassiopeia is ascending the north-northeast sky; she actually seems to resemble a sort of contorted number 3. At around 11 p.m. local daylight time, you'll find her soaring high above Polaris and most resembling an "M." 

Cassiopeia lies almost completely within the Milky Way, embedded within some marvelous fields of stars. Unlike the region around Sagittarius (which marks the center of our galaxy), we are looking out toward the outer edges of our galaxy when we face Cassiopeia. If you own a pair of binoculars, scan this region and you'll come across a number of eye-catching sights.

Double your starry pleasure

One object that will immediately catch your attention actually belongs not to Cassiopeia, but to an adjacent pattern of stars that represents her future son-in-law, Perseus. If you extend an imaginary line roughly 1.5 times the distance from the star Gamma to Delta Cass (also known as Ruchbah) and beyond, you'll come across a faint blur of light which binoculars will readily reveal as two concentrations of stars, called h Persei and Chi Persei: the Double Star Cluster of Perseus. 

The ancient astronomers Hipparchus and Ptolemy described them as a "cloudy spot." Galileo with his crude telescope first noticed they were really two clusters of stars. Astronomers estimate that their apparent brightness is dimmed thanks to interstellar dust. When we take this into account, it turns out that the ten brightest stars of this Double Cluster are actually comparable to such brilliant luminaries as Betelgeuse and Rigel in Orion, for each cluster contains very massive blue stars and some of the brightest red stars known. The blue stars are extremely hot, on the order of 100,000 degrees F. (55,500 degrees C.), blazing out energy so fast that they cannot keep it up for more than 10 million years, changing to red as they age. Estimates place these star clusters at distances of about 7,100 to 7,400 light years. Together, their apparent size in the sky exceeds that of the full Moon, and in binoculars or a small telescope form one of the most impressive and spectacular objects in the entire sky.

There are other clusters of stars to be found within Cassiopeia; a fascinating wealth of celestial treasures which indeed seem especially fitting for a Queen!

"Holed up" near the horizon

It makes sense that in our mid-October early evening night sky, that the celestial big bear is following his earthly cousins and also going into hibernation and seemingly is tucked away down along the northern horizon. What is remarkable is that these stars comprised a bear to widely separated early peoples — not only to Old World ancients but New World Native American tribes as well. There must be a reason why mankind has associated bears — particularly polar bears — with this star pattern. This in spite of the fact that the stars that comprise the handle of the Big Dipper also supposedly mark the tail of the bear; but here on Earth bear tails are short and stubby, however Ursa Major's tail is impossibly long. When Europeans landed in North America, they discovered to their amazement that some of the Indian tribes also made reference to these stars as a bear. 

The bear's nose is third-magnitude Muscida, a corruption of the Latin musus, meaning muzzle. The bear's paws, known to early Arabs as the "Leaps of the Gazelle" are marked by an almost equally spaced set of three pairs of stars. In all likelihood, the Arabs had never actually seen a bear, but they knew gazelles — small, swift and beautiful antelopes of the desert. So they imagined a gazelle bounding through this part of the sky, leaving three pairs of hoof prints in its wake. 

This week, as darkness falls, we can view Ursa Major, low in the northwest sky. Its lower extremities are out of view, lying below the horizon. With each passing hour, the Bear will crouch a little lower and by 11 p.m., it will be almost completely out of sight save for the Big Dipper. For localities north of 35-degrees latitude, the Dipper will appear sitting, right side up, just above the northern horizon.

An "out of balance" dipper

If you have carefully watched the sky, you almost certainly have noticed that when the sun and moon appear near to the horizon, they appear to be abnormally large in size; when higher up they appear noticeably smaller. This is known as the "moon illusion" and indeed, this effect also causes the constellations to appear much larger when hovering near the horizon. If you have a clear and unobstructed view of the northern horizon, the view of the Big Dipper just before midnight will be quite dramatic; it will appear abnormally large and will seemingly fill the lowest part of the northern sky.

Of course, as the hours pass, you'll notice that not only does the Dipper appear to shrink as it climbs up the sky, but the proportional size of the handle versus the bowl will also appear to change: When the handle is still close to the horizon as it begins its northeastward ascent — around 1 a.m. or 2 a.m. — it will look disproportionately large when compared to the bowl. Yet, it is only our eyes that are fooled. If you were to take a picture of the Big Dipper oriented in that position, it will appear quite normal. In fact, no matter what position it's photographed, the Dipper's size and shape will appear exactly the same. 

A happy accident?

Finally, the Navajo Indians called Ursa Major "The Whirling Male," and Cassiopeia "The Whirling Female." To this, British astronomer, artist and poet, Guy Ottewell asks, "Coincidence? — or could the constellation of the Whirling Queen date back to a time when mankind lived closer together?" 

We may never know.

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, the Farmers' Almanac and other publications. Follow us on Twitter @Spacedotcom and on Facebook.  

A band of eerie predawn light will put on a show for early risers over the next few weeks.

The phenomenon, known as zodiacal light, will be prominent along the eastern horizon before dawn between the autumnal equinox, which occurred on Thursday (Sept. 22), and the next full moon on Oct. 9.

Zodiacal light will be most visible in areas free from urban light pollution and will appear in the lower third of the sky next to the twin stars of Castor and Pollux in the constellation Gemini. If you're in the Northern Hemisphere, look for zodiacal light during the early predawn hours from late August into early November. For the Southern Hemisphere, the phenomenon will be most visible in the evening hours around sunset, appearing in the west. 

Related: Night sky, September 2022: What you can see tonight [maps]

Zodiacal light, also known as "false dawn," occurs when sunlight is scattered by interplanetary particles in the plane of the solar system, the same material that causes meteor showers. It will appear as a broad cone or wedge of faint light extending upwards from the eastern horizon into the ecliptic  — the path the sun appears to take in the sky. The zodiacal light will appear comparable in brightness to the Milky Way, and will even appear "milkier," or lighter in appearance, according to EarthSky.org. 

Zodiacal light is most visible around the equinoxes because it follows the path of the sun through the sky. During the equinoxes, the sun is positioned directly above the equator. This means sunlight hits the horizon at its most extreme vertical angle during these times, brightly illuminating the interplanetary dust that creates the "false dawn" phenomenon.

If you want to take a photo of zodiacal light, try a long exposure to make sure your camera can capture the glow. For capturing the best pictures of the zodiacal light you can, check out our recommendations for the best cameras for astrophotography and best lenses for astrophotography. 

Editor's Note: If you get a good photo of the zodiacal light and would like to share it with Space.com's readers, send your photo(s), comments, and your name and location to spacephotos@space.com.  

Follow Brett on Twitter at @bretttingley. Follow us on Twitter @Spacedotcom or on Facebook.  

There are several constellations in our northern sky that have similar counterparts in the southern sky. 

In our current evening sky, for instance, is the zodiacal constellation Pisces, composed of two fish tied together on a string or ribbon by their tails. One fish is composed of a faint circle of stars popularly known as the Circlet. "Pisces"' is the Latin word for "fishes"; the singular form is "piscis," and there is indeed a Southern Fish constellation, known as Piscis Austrinus. Using the Great Square of Pegasus, if you imagine a line drawn through the two stars on the right side of the Square (Markab and Scheat, also called Alpha Pegasi and Beta Pegasi) and go straight south, you'll arrive at Fomalhaut, the brightest star in Piscis Austrinus and the 18th brightest star in the sky. 

Another pair of counterparts are the Northern Crown (Corona Borealis) and the Southern Crown (Corona Australis). Both are roughly circular, and both are ancient star patterns, dating back to the time of the second-century astronomer Claudius Ptolemy or even earlier, perhaps to Hipparchus almost three centuries before. These crown constellations have also been called wreaths, indicating the very ancient type of distinctive head decoration made of beech, willow or laurel leaves and, in later times, copied from such in precious metal in what we now know as a crown.  

Related: Growing up observing the night skies from the Northern and Southern hemispheres

The Northern Crown

Corona Borealis is said to represent the crown given to Ariadne, daughter of Minos, the king of Crete, by Dionysus, the ancient Greek god of wine and a very bucolic character who would have considered a nicely intertwined wreath of vines a sufficient tribute. Ariadne, however, was reluctant to accept a marriage proposal from Dionysus (who was in mortal form), since she did not wish to marry a mortal after being deserted by Theseus, the mythical king and founder-hero of Athens.

To prove he was a god, Dionysus (or Bacchus, as the Romans called him) took off his crown and threw it into the heavens as a tribute to Ariadne. Satisfied, she married him and, in the process, became immortal herself. 

The Southern Crown

In contrast to the bejeweled Corona Borealis, Corona Australis is said to represent a crown or wreath of laurel or olive leaves. According to one story from Greek mythology, the crown belongs to Chiron, the wisest of all the centaurs.

Another story relating to the Southern Crown comes from the Roman poet Ovid's "Metamorphoses." Juno, Roman queen of the gods, discovered that her husband, Jupiter, was the lover of Semele, who was a mere mortal. Posing as Semele's maid, Juno suggested that Semele ask Jupiter to appear before her in all his glory. Jupiter was appalled at such a request yet did not refuse it. When she gazed upon Jupiter in all his glory, Semele was consumed by fire. Somehow, her unborn son was saved; he ultimately became Bacchus, who, in turn, honored his mother posthumously by placing the Southern Crown in the sky. 

So we can thank Bacchus (and the ancient Greeks and Romans) for both crowns becoming constellations.

Related: What's the story behind the stars?

The "second scoop"  

On September evenings, the Northern Crown stands halfway up in the western sky, while the Southern Crown lies close to the southern horizon, below the Teapot of Sagittarius. Both crowns attract almost immediate attention as the eye sweeps across them.  Seven stars, one of second magnitude (Gemma, the crown jewel), form the incomplete circle of Corona Borealis; it actually resembles a tiara rather than a crown.

When I gave sky shows at New York's Hayden Planetarium, however, the Northern Crown was something quite different: It was immediately adjacent to the top of the constellation Boötes, which resembles an elongated kite. But for my audiences, I suggested that Boötes was much better envisioned as an ice cream cone with two scoops. "Unfortunately, it appears that the second scoop has completely slipped off the top!" I'd say. And then I would point to Corona Borealis.  

The "lemon slice"

Despite its much fainter stars, which suffer from their low altitude for mid-northern observers, Corona Australis is quite attractive because there are so many more stars (11), and the circlet is practically complete. The late George Lovi (1939-1993), who was on the lecture staff of the Hayden Planetarium during the 1980s and early '90s, found a different use for this star pattern. First, he would point out the Teapot asterism of Sagittarius; then he would ask his audience if they would like lemon with their tea. He would then point to a slice of lemon: Corona Australis. 

"Do I hear that some of you prefer milk with your tea?" he would say. "The Milky Way flows right past!"   

Two odd stars

One of the more remarkable stars in the sky is R Coronae Borealis, popularly known as R Cor Bor. Put simply, it is a nova in reverse. Normally shining at magnitude 5.9, at completely irregular intervals, this star will suddenly fade, sometimes by as much as eight magnitudes (nearly 1,600 times), as dark clouds of carbon material, or "soot clouds," erupt in the star's atmosphere. Its brightness then slowly recovers as the material dissipates. The fall is quite rapid, and the return to normal is much slower, with occasional relapses. The fade-down of the bright red star Betelgeuse in Orion in 2019 likely was caused by a similar cloud of obscuring matter. 

And then there is T Coronae Borealis, also known as the Blaze Star, which currently shines at magnitude 10.2, making it 30 times dimmer than the faintest star on the threshold of naked-eye visibility. (Lower magnitudes indicate higher brightness, and vice versa.) But more than 150 years ago, on May 12, 1866, this star suddenly brightened to magnitude 2, becoming nearly as luminous as Polaris (the North Star). Known as a recurrent nova, T Coronae Borealis repeated the performance unexpectedly on the night of Feb. 9, 1946, and sometime in the future, it will probably do so again. 

In fact, considering the flare-ups of 1866 and 1946 were separated by almost exactly 80 years, perhaps another flare-up could be just around the corner.  

The one that got away

In his autobiography, "Starlight Nights," (Harper and Row, 1965) Leslie C. Peltier (sometimes called "the world's greatest nonprofessional astronomer") wrote that at every opportunity from 1920 on — more than 25 years — he kept a careful watch on T Coronae. But on the once-in-a-lifetime night in 1946 when the star suddenly brightened, Peltier was asleep!  

On that cold February morning, the alarm clock rang at 2:30 a.m., but upon awakening, Peltier sneezed a couple of times and thought he might be coming down with a cold, or maybe something worse. "Self-pity comes easy at 2:30 on a cold February morning," he later wrote, "so I went back to my warm bed."

Of course, after Peltier found out that he had missed out on the unexpected flare-up of the star he had been monitoring for more than a quarter of a century, he was not a happy camper. 

"I still have the feeling that T [Coronae Borealis] could have shown me more consideration," he wrote. "We had been friends for many years; on thousands of nights, I had watched over it as it slept, and then, it arose in my hour of weakness as I nodded at my post. I am still watching it, but now it is with a wary eye. There is no warmth between us anymore." 

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, the Farmers' Almanac and other publications. Follow us on Twitter @Spacedotcom and on Facebook.

A nebula is a giant cloud of gas and dust located in the space between stars. Nebula is Latin for "mist, vapor, fog, smoke, exhalation," but in an astronomical context, it refers to any celestial object that appears cloud-like when viewed through a telescope.

Some nebulas are formed when gas and dust are thrown out during a supernova —an explosion of a dying star, while other nebulas form through clouds of cold interstellar gas and dust. When these regions become dense enough they can spawn new stars, which is why nebulas are sometimes referred to as "stellar nurseries." 

Nebulas come in many shapes and sizes and can be further divided into several subcategories including planetary nebulas, supernova remnants, dark nebulas and emission nebulas. 

When telescopes weren't as powerful as today, this term encompassed galaxies such as our neighbor Andromeda, often referred to as the "Andromeda nebula". 

However, with the benefit of modern telescopes, we know that galaxies aren't cloud-like at all, but made up of billions of stars. This means astronomers now reserve the word nebula for genuine clouds — of gas and dust — located inside our own galaxy.

Related: What is the Eagle Nebula?

Where are nebula located?

Nebula are often found in the space between stars, known as the interstellar medium. On average, this region contains only around one atom per cubic centimetre. However, in certain places the density can be significantly higher than this ⁠— high enough to become visible through a telescope. 

The result is what we call a nebula, and they are among the most spectacular sights in astronomy. In fact many of the most iconic Hubble telescope images, such as the "Pillars of Creation", are images of nebula.

There are several different types of nebula, depending on how they form and their composition. Most nebula are primarily made of gas, which is able to glow with its own light, creating the colorful displays with which we are familiar . 

But other nebula ⁠— such as the so-called "dark nebula" ⁠— are much dustier in their composition, and rather than glowing this dust has the effect of blocking the light from more distant objects beyond it.

What are the different types of nebula?

The relationship between nebula and stars

Nebula play a key role in the life cycle of stars, both at their birth and death. Stars are born in dense clumps of gas, dust, and other material inside diffuse emission nebulae, also frequently referred to as "stellar nurseries". 

Hubble’s Pillars of Creation is in this category, as is the famous Orion Nebula ⁠— which you may well have seen for yourself through binoculars or a small telescope. 

The principal force at work here is gravity, which causes the tenuous interstellar medium to condense into a nebula, and gravity that causes clumps inside the nebula to collapse down into stars.

At the other end of a star’s life, we encounter a different type of emission nebula. Stars like the sun end their lives as highly compact white dwarfs, but as they shrink down into this phase they release clouds of gas which form a so-called "planetary nebula". This is a rather misleading name, because such nebula have nothing to do with planets.

Unlike diffuse emission nebula, these have a more clearly defined appearance, usually circular in shape, which reminded William Herschel of a planet when he first observed them in the 1780s.

Not all stars end their days in the relative serenity of a planetary nebula. A star that’s much more massive than the sun will eventually explode as a supernova, and the debris flung out from that explosion forms yet another kind of nebula called a supernova remnant. The most famous of these is the Crab Nebula, which is all that remains of a spectacular supernova that was observed by Chinese astronomers in 1054.

Seeing nebulas in living color

To capture the spectacular nature of nebulae, telescopes — such as the Hubble Space Telescope and the James Webb Space Telescope ( JWST) — use infrared radiation emitted by nebulae to create an image.   

The visible light emitted by stars forming in and around a nebula can be blocked by the dense cosmic clouds of gas and dust that make up a nebula. Therefore, scientists must look to other wavelengths of light that are emitted from the nebula, such as infrared radiation. 

Infrared cameras onboard the JWST have relieved some of the most detailed images of nebulae, such as the Southern Ring planetary nebula. The Southern Ring nebula — also known as NGC 3132 — is around 2,500 light-years away from Earth and home to a dying star at its core. 

Using its Near-Infrared Camera (NIRCam) and the Mid-Infrared Instrument (MIRI), the JWST has captured one of the most detailed images of the nebula. In the two images above, JWST has captured layers of gas and dust within the Southern Ring Nebula. Each layer has been created by the expulsion of cosmic matter from the central dying star. 

Additional resources

For more information about nebulae, check out "The Hubble Legacy: 30 Years of Discoveries and Image", by Jim Bell and "Planetary Nebulae and How to Observe Them (Astronomers' Observing Guides)", by Martin Griffiths. 

Bibliography

• The Planets, "Nebula Facts – A Guide To Nebulae", accessed July 2022. 
• Universe Today, "Nebulae: What Are They And Where Do They Come From?", accessed July 2022. 
• The University of Utah, "Nebula", accessed July 2022. 
• Australia Telescope National Facility, "Star Formation", July 2022. 
• Cosmos, "Emission Nebula", accessed July 2022. 
• James Miller, "What Are Nebulae And How Are They Formed?", Astronomy Trek, December 2014. 
• Andy Briggs, "What is a supernova", EarthSky, November 2020. 

SpaceX and OneWeb say their satellite-internet constellations can coexist.

The companies have written a joint letter to the U.S. Federal Communications Commission (FCC), declaring harmony in low Earth orbit (LEO) for spectrum coordination between their respective current and next generation broadband constellations. 

In the letter, which is dated June 13, SpaceX and OneWeb request that the FCC disregard previously filed dissenting comments regarding spectrum coordination in LEO. SpaceX and OneWeb both submitted proposals for their first-generation internet constellations to the FCC in 2016, followed by a second round of proposals in 2020 for each company's next-generation broadband satellites. Simultaneously, both SpaceX and OneWeb submitted complaints with the FCC in an attempt to get a leg up on each other. Now, it seems the companies are operating on friendlier terms. 

Related: SpaceX's Starlink megaconstellation launches in photos

To date, SpaceX has launched more than 2,700 of its Starlink satellites to LEO and has received FCC approval to bring that number up to 12,000. However, SpaceX's next-generation Starlink constellation, which will feature larger satellites launched by the company's huge Starship vehicle, may eventually harbor up to 30,000 spacecraft.

OneWeb has received similar permissions from the FCC for its plans to build a constellation of 648 broadband satellites and has expressed hopes to eventually bring that number up to 7,000 with upgraded spacecraft versions. The British startup has launched over half of its first-generation satellites, but that progress slowed earlier this year due to Russia's invasion of Ukraine. 

OneWeb had been launching its satellites aboard Russian-built Soyuz rockets. However, that partnership dissolved in the wake of the invasion, leaving OneWeb without a launch provider. 

In response, OneWeb turned to SpaceX, a competitor in the satellite internet market. In the first sign of easing tensions between the companies, OneWeb announced in March that it had awarded SpaceX a launch contract to help complete its first-generation constellation. Now, the two companies are taking another cooperative step. 

"After extensive good-faith coordination discussions, [SpaceX and OneWeb] are happy to inform the Commission that they agree that their respective first-round systems can efficiently coexist with each other, and that their respective second-round systems can also efficiently coexist," the companies' joint letter to the FCC reads, in part. 

They request that the regulatory commission "negate all prior-filed comments by either party against SpaceX's and OneWeb's 2016 Processing Round and 2020 Processing Round [applications]…" And, in light of their newfound harmony, SpaceX and OneWeb request that the FCC "quickly approve each second-round system so that they may begin deploying these cutting-edge systems." 

For SpaceX, second-round approval would mean clearing another hurdle toward an operational Starship mission. Starship, the company's massive new spacecraft under development, passed an environmental review by the U.S. Federal Aviation Administration earlier this month, putting the vehicle one step closer to an orbital test flight. 

SpaceX founder and CEO Elon Musk recently tweeted a video depicting Starship's planned Pez-like deployment of the heftier Starlink 2.0 satellite, which will be too massive for either SpaceX's Falcon 9 or Falcon Heavy rockets to launch efficiently. 

Follow us on Twitter @Spacedotcom or on Facebook.  

Birds of a feather may flock together here on Earth, but our avian friends are also well represented in the night sky as constellations named after winged creatures both real and imaginary. 

Take, for example, this recent image captured by NASA and ESA's Hubble Space Telescope of the barred spiral galaxy NGC 7496 in the constellation Grus, which is the Latin name for crane.  

Situated 24 million light-years from our big Blue Marble, this stellar configuration is one of four constellations that are collectively called the Southern Birds. Grus joins a trio of other bird-themed constellations known as Pavo (peacock), Phoenix (the mythical phoenix), and Tucana (toucan) to make up this sparkling nest of brilliant star formations.

Related: The best Hubble Space Telescope images of all time!

But beyond the Southern Birds, the heavens offer sanctuary for even more ornithological constellations like Aquilla (eagle), Cygnus (swan), Corvus (crow), Apus (bird-of-paradise), and Columba (dove).

In the mesmerizing swirl of violet-blue, silver-white and deep-red, Hubble's snapshots of NGC 7496 were gathered from multiple observations that explored the complex relationship between youthful stars and the cold, dense clouds of gas they were birthed within. 

Besides utilizing images obtained from Hubble's Wide Field Camera 3 and Advanced Camera for Surveys, NASA and ESA astronomers assigned to the project also collected data using the Atacama Large Millimeter/submillimeter Array (ALMA), with 66 radio telescopes offering unprecedented views of the stars from its base of operations, high in the Chilean Atacama Desert.

Discovering more about how fast and efficiently stars are formed amid a wide sampling of galactic environments is just one of the project's goals, which also include bolstering the data banks with a steady stream of detailed Hubble and ALMA observations. 

This pair of powerhouse observatories are contributing to a growing wealth of research material on star formation to aid further studies and assist upcoming investigations involving the newly-deployed James Webb Space Telescope.

Follow us on Twitter @Spacedotcom and on Facebook.

June presents a perfect opportunity to spot the three biggest constellations in the sky — Hydra, Virgo and Ursa Major — but you may have to look beyond standard star charts to find the Big Three. 

Over the more than two decades that I've been writing about stars and constellations for Space.com, readers have occasionally asked me why the constellation patterns differ from similarly designed star charts and are not standardized. There are two main reasons: People see constellations in different ways, and modern astronomy does not consider constellations as star pictures but rather as specific sky areas. 

All of the constellations shown in modern star atlases are officially approved by the International Astronomical Union (IAU), and the official boundaries for all 88 constellations were drawn up in 1930. Before that time, no two atlases agreed on the limits, and much confusion resulted.  

Related: See 5 planets align in the night sky this month in a rare treat!

To see these boundaries, we need to consult a star atlas. Standard star charts that show the night sky for a particular time of the night and that include only the principal stars visible to the naked eye do not give an accurate idea of a constellation's size. For example, a map of the United States, or even a map of New York state, does not help you find your way around Manhattan; for that, you need a detailed street map. Similarly, star charts designed to show the positions of the constellations for a specific time of the night are only intended to give an overview.

Soon after darkness falls on these early June evenings, the "Big Three" — that is, the three largest constellations in our sky, Hydra (the Water Serpent), Virgo (the Maiden) and Ursa Major (the Great Bear) — will be in full view. 

Overall, Hydra spans over 100 degrees of the sky and takes nearly seven hours to rise into full view. This tremendously long creature is not only the longest constellation but also the largest based on its area in square degrees, according to official boundaries established by the IAU. Hydra covers 1,304 square degrees, or about 3% of the entire sky, which isn't surprising considering the linear extent of this beast. 

But it is far less obvious that Virgo is the second-largest constellation, with an area of 1,294 square degrees, followed by Ursa Major, at 1,280 square degrees. 

Hence, the one-time picturesque patterns of people, animals and objects have evolved into arbitrarily defined areas of the sky. Let's take a closer look at these three big patterns that currently dominate our late-spring evening sky.

1. Hydra (the Water Serpent) 

June's warmer evenings inspire many of us to spend more time under the sky, perhaps to seek out the smaller and less-conspicuous constellations. Observers in an area with a dark sky and a wide-open view toward the southern part of the sky will enjoy tracing out the great length of Hydra, sometimes called the Water Serpent or the Snake. The imagery dates back to 1200 B.C. and may be related to a more important beast: the dragon Tiamat of the Euphratean epic about the hero Gilgamesh.  

Some also say, however, that Hydra commemorates the fabled multiheaded serpent that gave the mighty Hercules so much trouble. Yet our celestial Hydra has only one head, near the sickle of Leo. That head is a pretty little group of five stars worth looking for, about halfway between the bright stars Regulus and Procyon. From there, if the sky is clear and dark, you can follow the remaining scraggly stream of the snake's body; its zigzagging procession of faint stars leads south and east for more than an additional 90 degrees across the sky.  

Related: What's the story behind the stars?

Hydra's brightest star is the second-magnitude Alphard, an orange giant about 177 light-years away and sometimes called "The Solitary One." Once you've found it, you'll understand why it's so named: It seems brighter than it is, because it's in a large, dull region and has no competition nearby.  

Resting on the back of the Snake are two smaller constellations. Crater (the Cup) is a small, rather faint group. Farther south, though, where it rises higher, its graceful shape can be traced on a dark, clear night. Farther east is a little four-sided figure of fairly bright stars. This is Corvus (the Crow), which, like most constellations, bears little resemblance to the object it was supposed to represent; it's a small, moderately bright, quadrilateral-shaped pattern of stars.  Add a fainter adjoining star, and the pattern resembles the battened mainsail of a Chinese junk. 

Hydra, Crater and Corvus are connected by a myth: Corvus was the messenger of the god Apollo. Sent by the god to fetch a drink of water in the Cup, the Crow dallied under a fig tree until the figs were ripe to eat, then came home without the Cup but in the fangs of the Snake as an alibi. Thereupon the angry Apollo put Snake, Cup and Crow in the sky. 

2. Virgo (the Maiden) 

Occupying much of the southern sky these early evenings is the large, faint constellation Virgo (the Maiden). Unlike most of the ancient constellations, Virgo presents no distinctive pattern of stars to attract attention; most star maps show it resembling the letter Y written in cursive style. In Greek and Roman tradition, Virgo was identified with the goddess of justice, Astraea, who ruled the world during the fabled Golden Age. It has also been suggested that the Sphinx represents both Leo and Virgo, each of which hosts the sun during the Nile's crucial annual flooding.  

In the old allegorical star books, the goddess holds some spikes of wheat in each hand, and her brightest star, bluish Spica, glows in one of the ears of grain hanging from her left hand. I predict that in 2026, Spica will get a lot of attention in the news media — not so much because it is among the brightest stars (it ranks 16th), but because the current and most definitive estimates of its distance place it at 250 light-years away. Thus, from July 4 through Aug. 2, 2026, those who look at Spica might very well be witnessing light that started on its journey toward Earth during the same time frame the Founding Fathers signed the Declaration of Independence.  

Might, then, the media refer to Spica as "America's star"? (I should also point out that the true distance of Spica is known to within an accuracy of only +/- 10 light-years, so the starlight from 1776 may have already reached us or may not get here until 2036.)

Also located within Virgo is one of the most remarkable areas of the heavens, known as the Realm of the Galaxies. Here lies a celestial wonderland of star "cities," an amazing concentration of dimly luminous patches. Literally thousands of galaxies have been photographed here with great observatory instruments. Every one of these dim blobs is a star city, and the assertion by reputable astronomers is that the average mass of each galaxy is some 200 billion times the mass of the sun. The best estimates indicate that these star cities are located somewhere between 40 million and 70 million light-years from Earth.  

3. Ursa Major (the Great Bear) 

Late spring is when the Great Bear prowls the evening night sky almost directly overhead for most stargazers in the Northern Hemisphere. Scholars are fairly sure that the oldest star groups trace back to the people of Mesopotamia five or more millennia ago. In fact, the creatures that were made into the ancient Western constellations are similar to those in the Bible, and there are hints that some are far older. The fact that the Big Dipper formed a bear to Native Americans and to the cultures of the Old World and Siberia suggests that Ursa Major is a piece of Stone Age culture dating to at least 8,000 to 12,000 years ago, which is the estimated era of the last migration from Siberia to North America across the Bering Strait. 

For much of the world, this pattern has been, if not a bear, some sort of wagon. Shakespeare's "Henry IV" refers to the Big Dipper as Charles' Wain. (A wain is a large, open farm wagon.) In Great Britain, it is better known as the Plough. But the Big Dipper visualized as a ladle is strictly an American phenomenon; this celestial "drinking gourd" was often mentioned in mid-19th-century books, but not before then. 

As such, the Big Dipper itself has been a source of frustration to some constellation historians.  Who invented this name? Nobody seems to know.

To envision the entire star pattern as a "Big Bear," the bear's nose is marked by the third-magnitude star Muscida. The bear's paws, known to early Arabs as the "Leaps of the Gazelle," are marked by an almost equally spaced set of three pairs of stars. The Dipper's bowl is the torso. 

So what explains the abnormally long tail marked by the Dipper's handle? No bear that has ever walked Earth has possessed anything more than a stubby tail. But 19th-century British writer Thomas Hood once speculated as to the reason: 

"Imagine that Jupiter, fearing to come too nigh unto her teeth, lay hold on her tail, and thereby drew her up into the heaven; so that she of herself being very weighty, and the distance from the earth to the heavens very great, there was great likelihood that her tail must stretch," Hood wrote. "Other reason know I none."

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, the Farmers' Almanac and other publications. Follow us on Twitter @Spacedotcom and on Facebook. 

Stars are giant, luminous spheres of plasma. There are billions of them — including our own sun — in the Milky Way galaxy. And there are billions of galaxies in the universe. So far, we have learned that hundreds of stars also have planets orbiting them.

How are stars formed?

A star develops from a giant, slowly rotating cloud that is made up entirely or almost entirely of hydrogen and helium. Due to its own gravitational pull, the cloud begins to collapse inward, and as it shrinks, it spins more and more quickly, with the outer parts becoming a disk while the innermost parts become a roughly spherical clump. 

According to NASA, this collapsing material grows hotter and denser, forming a ball-shaped protostar. When the heat in the protostar reaches about 1.8 million degrees Fahrenheit (1 million degrees Celsius), atomic nuclei that normally repel each other start fusing together, and the star ignites. Nuclear fusion converts a small amount of the mass of these atoms into extraordinary amounts of energy — for instance, 1 gram of mass converted entirely to energy would be equal to an explosion of roughly 22,000 tons of TNT.

Stellar evolution

The life cycles of stars follow patterns based mostly on their initial mass. These include intermediate-mass stars such as the sun, with half to eight times the mass of the sun, high-mass stars that are more than eight solar masses, and low-mass stars a tenth to half a solar mass in size. The greater a star's mass, the shorter its lifespan generally is, according to NASA. Objects smaller than a tenth of a solar mass do not have enough gravitational pull to ignite nuclear fusion — some might become failed stars known as brown dwarfs.

An intermediate-mass star begins with a cloud that takes about 100,000 years to collapse into a protostar with a surface temperature of about 6,750 degrees F (3,725 degrees C). After hydrogen fusion starts, the result is a T-Tauri star, a variable star that fluctuates in brightness. This star continues to collapse for roughly 10 million years until its expansion due to energy generated by nuclear fusion is balanced by its contraction from gravity, after which point it becomes a main-sequence star that gets all its energy from hydrogen fusion in its core.

The greater the mass of such a star, the more quickly it will use its hydrogen fuel and the shorter it stays on the main sequence. After all the hydrogen in the core is fused into helium, the star changes rapidly — without nuclear radiation to resist it, gravity immediately crushes matter down into the star's core, quickly heating the star. This causes the star's outer layers to expand enormously and to cool and glow red as they do so, rendering the star a red giant. 

Helium starts fusing together in the core, and once the helium is gone, the core contracts and becomes hotter, once more expanding the star but making it bluer and brighter than before, blowing away its outermost layers. After the expanding shells of gas fade, the remaining core is left, a white dwarf that consists mostly of carbon and oxygen with an initial temperature of roughly 180,000 degrees F (100,000 degrees C). Since white dwarves have no fuel left for fusion, they grow cooler and cooler over billions of years to become black dwarves too faint to detect. Our sun should leave the main sequence in about 5 billion years, according to Live Science.

A high-mass star forms and dies quickly. These stars form from protostars in just 10,000 to 100,000 years. While on the main sequence, they are hot and blue, some 1,000 to 1 million times as luminous as the sun and are roughly 10 times wider. When they leave the main sequence, they become a bright red supergiant and eventually become hot enough to fuse carbon into heavier elements. After some 10,000 years of such fusion, the result is an iron core roughly 3,800 miles (6,000 km) wide, and since any more fusion would consume energy instead of liberating it, the star is doomed, as its nuclear radiation can no longer resist the force of gravity.

When a star reaches a mass of more than 1.4 solar masses, electron pressure cannot support the core against further collapse, according to NASA. The result is a supernova. Gravity causes the core to collapse, making the core temperature rise to nearly 18 billion degrees F (10 billion degrees C), breaking the iron down into neutrons and neutrinos. In about one second, the core shrinks to about six miles (10 km) wide and rebounds just like a rubber ball that has been squeezed, sending a shock wave through the star that causes fusion to occur in the outlying layers. The star then explodes in a so-called Type II supernova. If the remaining stellar core was less than roughly three solar masses large, it becomes a neutron star made up nearly entirely of neutrons, and rotating neutron stars that beam out detectable radio pulses are known as pulsars. If the stellar core was larger than about three solar masses, no known force can support it against its own gravitational pull, and it collapses to form a black hole.

A low-mass star uses hydrogen fuel so sluggishly that they can shine as main-sequence stars for 100 billion to 1 trillion years — since the universe is only about 13.7 billion years old, according to NASA, this means no low-mass star has ever died. Still, astronomers calculate these stars, known as red dwarfs, will never fuse anything but hydrogen, which means they will never become red giants. Instead, they should eventually just cool to become white dwarfs and then black dwarves.

History of star observations

Since the dawn of recorded civilization, stars played a key role in religion and proved vital to navigation, according to the International Astronomical Union. Astronomy, the study of the heavens, may be the most ancient of the sciences. The invention of the telescope and the discovery of the laws of motion and gravity in the 17th century prompted the realization that stars were just like the sun, all obeying the same laws of physics. In the 19th century, photography and spectroscopy — the study of the wavelengths of light that objects emit — made it possible to investigate the compositions and motions of stars from afar, leading to the development of astrophysics. 

In 1937, the first radio telescope was built, enabling astronomers to detect otherwise invisible radiation from stars. The first gamma-ray telescope launched in 1961, pioneering the study of star explosions (supernovae). Also in the 1960s, astronomers commenced infrared observations using balloon-borne telescopes, gathering information about stars and other objects based on their heat emissions; the first infrared telescope (the Infrared Astronomical Satellite) was launched in 1983. 

Microwave emissions were first studied from space in 1992, with NASA's Cosmic Microwave Background Explorer (COBE) satellite. (Microwave emissions are generally used to probe the young universe's origins, but they are occasionally used to study stars.) In 1990, the first space-based optical telescope, the Hubble Space Telescope, was launched, providing the deepest, most detailed visible-light view of the universe.

There have been, of course, more advanced observatories (in all wavelengths) over the years, and even more powerful ones are planned. A couple of examples are the Extremely Large Telescope (ELT), which is planned to start observations in 2024 in infrared and optical wavelengths. Also, NASA's James Webb Space Telescope – billed as a successor to Hubble – will launch in 2018 to probe stars in infrared wavelengths.

How are stars named?

Ancient cultures saw patterns in the heavens that resembled people, animals or common objects — constellations that came to represent figures from myth, such as Orion the Hunter, a hero in Greek mythology. 

Astronomers now often use constellations in the naming of stars. The International Astronomical Union, the world authority for assigning names to celestial objects, officially recognizes 88 constellations. Usually, the brightest star in a constellation has "alpha," the first letter of the Greek alphabet, as part of its scientific name. The second brightest star in a constellation is typically designated "beta," the third brightest "gamma," and so on until all the Greek letters are used, after which numerical designations follow.

A number of stars have possessed names since antiquity — Betelgeuse, for instance, means "the hand (or the armpit) of the giant" in Arabic. It is the brightest star in Orion, and its scientific name is Alpha Orionis. Also, different astronomers over the years have compiled star catalogs that use unique numbering systems. The Henry Draper Catalog, named after a pioneer in astrophotography, provides spectral classification and rough positions for 272,150 stars and has been widely used by the astronomical community for over half a century. The catalog designates Betelgeuse as HD 39801.

Since there are so many stars in the universe, the IAU uses a different system for newfound stars. Most consist of an abbreviation that stands for either the type of star or a catalog that lists information about the star, followed by a group of symbols. For instance, PSR J1302-6350 is a pulsar, thus the PSR. The J reveals that a coordinate system known as J2000 is being used, while the 1302 and 6350 are coordinates similar to the latitude and longitude codes used on Earth.

In recent years, the IAU formalized several names for stars amid calls from the astronomical community to include the public in their naming process. The IAU formalized 14 star names in the 2015 "Name ExoWorlds" contest, taking suggestions from science and astronomy clubs around the world.

Then in 2016, the IAU approved 227 star names, mostly taking cues from antiquity in making its decision. The goal was to reduce variations in star names and also spelling ("Formalhaut", for example, had 30 recorded variations.) However, the long-standing name "Alpha Centauri" – referring to a famous star system with planets just four light-years from Earth – was replaced with Rigel Kentaurus.

Binary stars and other multiples

Although our solar system only has one star, most stars like our sun are not solitary but are binaries, where two stars or multiple stars orbit each other. In fact, just one-third of stars like our sun are single, while two-thirds are multiples — for instance, the closest neighbor to our solar system, Proxima Centauri, is part of multiple systems that also includes Alpha Centauri A and Alpha Centauri B. Still, class G stars like our sun only make up some 7% of all the stars we see — when it comes to systems in general, about 30 percent in our galaxy are multiple, while the rest are single, according to Charles J. Lada of the Harvard-Smithsonian Center for Astrophysics.

Binary stars develop when two protostars form near each other. One member of this pair can influence its companion if they are close enough together, stripping away matter in a process called mass transfer. If one of the members is a giant star that leaves behind a neutron star or a black hole, an X-ray binary can form, where matter pulled from the stellar remnant's companion can get extremely hot — more than 1 million F (555,500 C) and emit X-rays. 

If a binary includes a white dwarf, gas pulled from a companion onto the white dwarf's surface can fuse violently in a flash called a nova. At times, enough gas builds up for the dwarf to collapse, leading its carbon to fuse nearly instantly and the dwarf to explode in a Type I supernova, which can outshine a galaxy for a few months.

Key characteristics of stars

Brightness

Astronomers describe star brightness in terms of magnitude and luminosity.

The magnitude of a star is based on a scale more than 2,000 years old, devised by Greek astronomer Hipparchus around 125 BC, according to NASA's Ask and Astrophysicist. He numbered groups of stars based on their brightness as seen from Earth — the brightest stars were called first magnitude stars, the next brightest were the second magnitude, and so on up to sixth magnitude, the faintest visible ones. 

Nowadays astronomers refer to a star's brightness as viewed from Earth as its apparent magnitude, but since the distance between Earth and the star can affect the light one sees from it, they now also describe the actual brightness of a star using the term absolute magnitude, which is defined by what its apparent magnitude would be if it were 10 parsecs or 32.6 light-years from Earth. The magnitude scale now runs to more than six and less than one, even descending into negative numbers — the brightest star in the night sky is Sirius, with an apparent magnitude of -1.46.

Luminosity is the power of a star — the rate at which it emits energy. Although power is generally measured in watts — for instance, the sun's luminosity is 400 trillion trillion watts— the luminosity of a star is usually measured in terms of the luminosity of the sun. For example, Alpha Centauri A is about 1.3 times as luminous as the sun. To figure out luminosity from absolute magnitude, one must calculate that a difference of five on the absolute magnitude scale is equivalent to a factor of 100 on the luminosity scale — for instance, a star with an absolute magnitude of 1 is 100 times as luminous as a star with an absolute magnitude of 6.

The brightness of a star depends on its surface temperature and size.

Color

Stars come in a range of colors, from reddish to yellowish to blue. The color of a star depends on surface temperature.

A star might appear to have a single color, but actually emits a broad spectrum of colors, potentially including everything from radio waves and infrared rays to ultraviolet beams and gamma rays. Different elements or compounds absorb and emit different colors or wavelengths of light, and by studying a star's spectrum, one can divine what its composition might be.

Surface temperature

Astronomers measure star temperatures in a unit known as the kelvin, with a temperature of zero K ("absolute zero") equaling minus 273.15 degrees C, or minus 459.67 degrees F. A dark red star has a surface temperature of about 2,500 K (2,225 C and 4,040 F); a bright red star, about 3,500 K (3,225 C and 5,840 F); the sun and other yellow stars, about 5,500 K (5,225 C and 9,440 F); a blue star, about 10,000 K (9,725 C and 17,540 F) to 50,000 K (49,725 C and 89,540 F).

The surface temperature of a star depends in part on its mass and affects its brightness and color. Specifically, the luminosity of a star is proportional to temperature to the fourth power. For instance, if two stars are the same size but one is twice as hot as the other in kelvin, the former would be 16 times as luminous as the latter.

Related: How hot is the sun?

Size

Astronomers generally measure the size of stars in terms of the radius of our sun. For instance, Alpha Centauri A has a radius of 1.05 solar radii (the plural of radius). Stars range in size from neutron stars, which can be only 12 miles (20 kilometers) wide, to supergiants roughly 1,000 times the diameter of the sun.

The size of a star affects its brightness. Specifically, luminosity is proportional to radius squared. For instance, if two stars had the same temperature, if one star was twice as wide as the other one, the former would be four times as bright as the latter.

Mass

Astronomers represent the mass of a star in terms of the solar mass, the mass of our sun. For instance, Alpha Centauri A is 1.08 solar masses.

Stars with similar masses might not be similar in size because they have different densities. For instance, Sirius B is roughly the same mass as the sun but is 90,000 times as dense, and so is only a fiftieth its diameter.

The mass of a star affects surface temperature.

Magnetic field

Stars are spinning balls of roiling, electrically charged gas, and thus typically generate magnetic fields. When it comes to the sun, researchers have discovered its magnetic field can become highly concentrated in small areas, creating features ranging from sunspots to spectacular eruptions known as flares and coronal mass ejections. A survey at the Harvard-Smithsonian Center for Astrophysics found that the average stellar magnetic field increases with the star's rate of rotation and decreases as the star ages.

Metallicity

The metallicity of a star measures the amount of "metals" it has — that is, any element heavier than helium.

Three generations of stars may exist based on metallicity. Astronomers have not yet discovered any of what should be the oldest generation, Population III stars born in a universe without "metals." When these stars died, they released heavy elements into the cosmos, which Population II stars incorporated relatively small amounts of. When a number of these died, they released more heavy elements, and the youngest Population I stars like our sun contain the largest amounts of heavy elements.

Star classification

Stars are typically classified by their spectrum in what is known as the Morgan-Keenan or MK system, according to the European Southern Observatory. There are eight spectral classes, each analogous to a range of surface temperatures — from the hottest to the coldest, these are O, B, A, F, G, K, M and L. Each spectral class also consists of 10 spectral types, ranging from the numeral 0 for the hottest to the numeral 9 for the coldest.

Stars are also classified by their luminosity under the Morgan-Keenan system. The largest and brightest classes of stars have the lowest numbers, given in Roman numerals — Ia is a bright supergiant; Ib, a supergiant; II, a bright giant; III, a giant; IV, a subgiant; and V, a main sequence or dwarf.

A complete MK designation includes both spectral type and luminosity class — for instance, the sun is a G2V. 

Stellar structure

The structure of a star can often be thought of as a series of thin nested shells, somewhat like an onion.

A star during most of its life is a main-sequence star, which consists of a core, radiative and convective zones, a photosphere, a chromosphere and a corona. The core is where all the nuclear fusion takes place to power a star. 

In the radiative zone, energy from these reactions is transported outward by radiation, like heat from a light bulb, while in the convective zone, energy is transported by the roiling hot gases, like hot air from a hairdryer. Massive stars that are more than several times the mass of the sun are convective in their cores and radiative in their outer layers, while stars comparable to the sun or less in mass are radiative in their cores and convective in their outer layers. Intermediate-mass stars of spectral type A may be radiative throughout.

After those zones come the part of the star that radiates visible light, the photosphere, which is often referred to as the surface of the star. After that is the chromosphere, a layer that looks reddish because of all the hydrogen found there. Finally, the outermost part of a star's atmosphere is the corona, which if super-hot might be linked with convection in the outer layers.

Additional resources

To explore the stars of our universe for yourself, you can use NASA's Skymap tool. Additionally, to see images of stars taken by the Hubble Space Telescope, browse the European Space Agency's (ESA) image archive.

Bibliography

Salaris, M., & Cassisi, S. (2005). "Evolution of stars and stellar populations". John Wiley & Sons. https://books.google.co.uk

"Spectral Classification". Annual Review of Astronomy and Astrophysics (1973). https://www.annualreviews.org/doi/abs/10.1146/annurev.aa.11.090173.000333?journalCode=astro

"The Gas–Star Formation Cycle in Nearby Star-forming Galaxies. I. Assessment of Multi-scale Variations".  The Astrophysical Journal (2019). https://iopscience.iop.org/article/10.3847/1538-4357/ab50c2/meta

Amazon has booked rides to space for the majority of its internet-satellite megaconstellation.

The company announced today (April 5) that it has signed contracts for up to 83 launches, which will loft the bulk of Amazon's 3,236 "Project Kuiper" internet satellites. The package of deals is "the largest commercial procurement of launch vehicles in history," company representatives said in a statement.

Amazon has secured 18 launches of Arianespace's Ariane 6 rocket, 38 flights of United Launch Alliance's (ULA) Vulcan Centaur and 12 missions (plus an option for 25 more) of Blue Origin's New Glenn heavy lifter. (Blue Origin and Amazon were both founded by Jeff Bezos, the world's second-richest person.)

Related: What is a satellite?

Amazon did not disclose the value of any of the contracts.

"We still have lots of work ahead, but the team has continued to hit milestone after milestone across every aspect of our satellite system," Dave Limp, senior vice president for Amazon Devices and Services, said in the same statement. "These launch agreements reflect our incredible commitment and belief in Project Kuiper, and we’re proud to be working with such an impressive lineup of partners to deliver on our mission."

Notably, those partners do not include SpaceX, whose Starlink broadband constellation is already providing service to customers around the world. SpaceX has launched more than 2,300 Starlink satellites to date using its workhorse Falcon 9 rocket and could end up lofting about 30,000 more.

Unlike the Falcon 9, the rockets that Amazon just picked to launch the Project Kuiper satellites aren't yet up and running. The Ariane 6 and Vulcan Centaur are expected to debut later this year, Arianespace and ULA representatives have said. New Glenn's first launch likely won't occur before 2023.

It's unclear why SpaceX didn't receive a Project Kuiper launch contract. But, as Ars Technica's Eric Berger noted, it likely didn't boil to competitive instinct on SpaceX's part; Elon Musk's company recently signed on to launch OneWeb internet satellites that were originally supposed to fly on Russian-built Soyuz rockets. (OneWeb's Soyuz deal with Arianespace, which was operating the rockets, fell apart after Russia invaded Ukraine.)

Amazon plans to launch two Project Kuiper prototype craft later this year on ABL Space Systems' RS1 rocket. Amazon also holds a pre-existing Project Kuiper deal for nine launches on ULA's Atlas V.

Mike Wall is the author of "Out There" (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or on Facebook.  

Believe it or not, there are four dogs that are currently traipsing through our early spring skies. 

Two are scampering for attention in the west that contain constellations associated with the winter season and will soon be bidding us a fond adieu. But there are two more ascending in the east — a star pattern that will be with us all through spring and summer months. Here, we'll describe each one. It's the 'leash' we can do.

(By the way, if you're looking for binoculars or telescopes to spot the stars of these cosmic pooches, check out our guides for the best binoculars and best telescopes. Our best cameras for astrophotography and best lenses for astrophotography guides can also help you find the right gear for your next starry night photo session.)

The dog star

The brightest of all the stars shines prominently this week about 90 minutes after sunset, about one-third of the way up from the south-southwest horizon. Sirius, the 'Dog Star' is the brightest star of the constellation which bears the Latin name Canis Major — the Big Dog. It is also the unquestionable ruler in its own section of the sky; a truly dazzling object, shining with an unmistakable brilliance. In color, the star is a brilliant white with a definite tinge of blue, but when the air is unsteady it then seems to flicker in rapid scintillation with all the colors of the rainbow. At a distance of 8.7 light-years, Sirius is the fifth nearest star known. Among the naked-eye stars, it is the nearest of all, with the exception of Alpha Centauri. 

Four thousand years ago, the ancient Egyptians noticed that Sirius would rise just before dawn at the time of the summer solstice apparently heralding the coming rise of the Nile, upon which Egyptian agriculture and all life in Egypt depended. Hence, Sirius became known as the 'Nile Star' or 'Star of Isis.'

More recently, the scorching heat of July and early August was attributed by some to when Sirius rises with the sun at that time of the year. Its brightness purportedly adds to the sun's energy, producing additional warmth and bringing forth fever in men and madness in dogs. Thus, the term 'Dog Days'.

Overshadowed by Sirius

Maybe you've heard of the idiom: 'The tail wags the dog'. Similarly, Sirius seems to get all the attention compared to the rest of its host constellation. 

Indeed, the rest of the constellation of Canis Major is quite overshadowed by the allure and radiance of its most noteworthy star. The rest of the dog is there, composed of triangular hindquarters and a long body. His muzzle and paws are uplifted as though he was bounding across the skies after his master, Orion the Mighty Hunter. Sirius is considered by some to be the Big Dog's nose; others say it marks his dog tag. 

Sirius' blinding presence also overwhelms a neighboring star, Adhara, located within the triangle of stars situated to the lower left of the Dog Star. Adhara marks the lower right of the triangle and shines at magnitude +1.50 and ranks as the twenty-second brightest overall in the sky. Yet by virtue of binning, misses by just a shade, the cutoff for first-magnitude classification. Here's another dramatic example of how appearances can be deceiving. Adhara is actually over 1,500 times more luminous than Sirius. But because it's 430 light-years away as compared to just 8.7 for Sirius, Adhara appears only 1/15 as bright.

Orion's 'second hound'

The intriguing names of the constellations may lead one to expect astronomy books to show groups of stars in the shape of a lion, an eagle, a bear and other animals and figures. But many show nothing of the sort. Some books show the constellations as involved geometrical shapes, which in many cases do not look like anything and have no relation to their names. And when darkness falls this week, we see the antithesis of a complex sky pattern in Canis Minor, the Little Dog, Orion's other dog and Canis Major's playful smaller companion. 

This smaller canine is situated about halfway up in the south-southwest and almost directly above Sirius. The Little Dog is composed of just two stars. The brighter of these two is the 'Little Dog Star' known as Procyon, the eighth-brightest star in the sky. The fainter of the two is called Gomeisa. 

Procyon is a yellow-white star, seven times as luminous as the Sun and 11 light-years away. The name Procyon has been in use since the days of ancient Greece. It is the equivalent of the Latin word 'Antecanis' or 'Before the Dog,' an allusion to the fact that Procyon rises immediately preceding Sirius, and thus heralds the appearance of the great Dog Star. From mid-northern latitudes, Procyon comes above the east-northeast horizon about 25 minutes before Sirius first appears to blaze in the east-southeast. 

Interestingly, though, at this time of year, we notice that Procyon actually marches behind its more brilliant companion. How is it possible that the Little Dog rises before the larger one and yet follows it across the southern sky? The answer is that while Procyon is east of Sirius, it is also farther north so that it rises earlier, just as the sun comes up sooner in the morning when it's well north of the celestial equator in the summertime. 

Both Canis Major and Canis Minor are associated with the winter season, so they will both soon be departing our evening sky. Sirius and the Big Dog will be gone by the end of April; Procyon and the Little Dog, however, will linger in the west-northwest until the start of June.

Two more hunting dogs in the night sky

About halfway up in the east-northeast sky during the mid-evening hours, this week is a star pattern known as Canes Venatici, the Hunting Dogs. Located about a third of the way from the end of the Big Dipper's handle and below it, these dogs were placed in the sky to assist Boötes, the Bear Driver in his daily task of pursuing the Big Bear (Ursa Major) around the pole of the heavens. They used to be imagined as chasing the Great Bear around the pole. 

Like Canis Minor, there are only two stars that mark the Hunting Dogs, the brightest of which is Cor Caroli, known as 'the Heart of Charles.' A popular story is that the star was so-named by Edmund Halley in honor of King Charles II of England. This was supposedly done at the suggestion of the court physician Sir Charles Scarborough, who claimed that 'It shone with a special brilliance on the eve of the King's return to London on May 29, 1660.' However, upon delving deeper into this star's history, it is found that this star's original name was 'Cor Caroli Regis Martyris' honoring the executed Charles I. Cor Caroli marks the position of 'Chara,' one of the two hunting dogs in the mythological outline of the constellation. The other dog is named 'Asterion' and is marked by another, fainter star.

Cor Caroli is noteworthy today because of its high abundance of manganese, silicon, chromium, strontium, and the rare Earth metal europium. Its nonpolitical name, used by astronomers, has become the general term for a class of stars with the same peculiar makeup: the Alpha Canum Venaticorum stars. 

Canes Venatici will remain in view all through the rest of the spring and summer, before finally slipping out of sight in the northwest evening sky by early fall.

The constellation of the hot dog

As was noted earlier, both Canes Venatici and Canis Minor are each composed of just two stars. It is hard enough to try and envision a little dog (or anything else for that matter) out of just two stars. When I'm either outside pointing out the stars to campers or inside the 'pretend universe' of a planetarium, I ask my audience to envision the two stars of Canis Minor as a hot dog — but without the bun. 

Many years ago, in a pre-recorded sky show at New York's Hayden Planetarium, the lecturer on the tape said: 'You are somehow expected to see a little dog here, using Procyon and a neighboring star.' A voice in the dark called out, 'I see it!' The next line on the tape was, 'If you do see a dog here, perhaps you had better see a doctor too.' 

The lecturer's next few lines were hard to hear over the laughter of the audience. 

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, the Farmers' Almanac and other publications. Follow us on Twitter @Spacedotcom and on Facebook 

Look up tonight (March 15) to see the Hyades star cluster light up the Taurus constellation in the night sky.

The Hyades star cluster is the closest star cluster to Earth, located only 150 light-years away. Viewers can spot the star cluster by looking for the tall, Y-shaped constellation Taurus, the bull, which is situated high in the southwest sky on March evenings. The Hyades star cluster lies near the center of the constellation, forming the bull's face, according to NASA's March viewing guide. 

Another trick to spot the Hyades star cluster is to use the stars of Orion's belt as a guide to locate the bright orange star Aldebaran. While Aldebaran isn't actually part of the star cluster, it is located halfway to Hyades and conveniently visible in the foreground, as a part of the V-shaped grouping of stars that comprises the bull's head. 

Related: March night sky wonders: Strange sights to see every year

The Hyades grouping, containing hundreds of stars, is classified as an open star cluster because it's stars are close together in space, yet loosely bound together by their mutual gravity. While the stars formed together around the same time and from the same cloud of dust and gas, the leftover nebula material was blown away and the stars drifted apart, giving them an open, or diffuse, structure. 

"Our own sun formed in a cluster like this," according to the NASA statement. "Studying these structures helps us understand how stars form and evolve." 

The Pleiades star cluster, also known as the Seven Sisters, is another well-known open cluster located in the constellation Taurus. While the Hyades and the Pleiades star clusters are about the same size, measuring roughly 15 light-years across, the Pleiades cluster is about 3 times farther away. As a result, the Pleiades cluster appears more compact.

The Hyades star cluster is visible to the naked eye tonight in the first few hours after dark and should be easy to spot in the night sky, given its compact and distinctive shape. While skywatchers will be able to see a handful of stars with the unaided eye, viewers looking to see more stars — up to a hundred or more — will need to use binoculars. 

Our helpful guide for the best telescopes and best binoculars can help you find the right instrument. And, if you're hoping to snap photos of the star cluster, here are our guides for the best cameras for astrophotography and best lenses for astrophotography.

Editor's note: If you have an amazing night sky photo or video of the Hyades star cluster that you'd like to share for a possible story or image gallery, let us know! You can send in images and comments to spacephotos@space.com.

Follow Samantha Mathewson @Sam_Ashley13. Follow us on Twitter @Spacedotcom and on Facebook.  

Last month marks my 20th year writing the Night Sky column for Space.com. It is difficult for me to believe that in this forum I have penned over a thousand columns on a variety of different subjects covering space and stargazing. 

Among my constellation essays, I've probably written about the Orion constellation, the Hunter, more than any other and with good reason: No other star pattern can be compared to it. It has been recognized as perhaps the most eye-catching and extraordinary pattern of stars; a veritable treasure-trove of celestial wonders, containing two of the brightest stars, Rigel and Betelgeuse accompanied by its three belt stars in a distinctive diagonal row.

Related: Constellations of the western zodiac

Legends of Orion

Last month was most definitely the month of Orion; as the last bit of evening twilight fades away, we see him standing triumphantly high in the southern sky. There are numerous legends surrounding Orion. And there is more than one story of how he met his death. Orion liked to boast that no animal could ever escape him. This miffed the goddess Juno, so one day while Orion was pursuing a hare, she had a scorpion sting Orion on his heel, killing him.

This particular story was surely invented to account for the position, on opposite sides of the sky, of these two striking and easily recognized and very ancient constellations. When, on May evenings, the Scorpius constellation, the Scorpion, rises in the east-southeast, Orion quickly disappears below the western horizon, and not until the fall when Scorpius is setting does Orion appear again in the east. Hence it was thought that the mighty warrior was fleeing from his fatal adversary. 

Other legends about Orion include the Chaldeans who know him as Tammuz, named after the month in which Orion's familiar belt stars first rose before the sunrise. The Syrians referred to Orion as Al Jabbar, "The Giant." To the ancient Egyptians he was Sahu, the soul of Osiris.

Related: Book reviews for three guides to the stars and constellations

In yet another story, Diana, goddess of the moon, fell in love with Orion and neglected her task of lighting the night sky, often preferring to follow him and leaving the night sky in darkness. Her twin brother, Apollo, the sun-god, was furious. Bad enough the chariot of the moon lay idle, but it was disgraceful that his sister fell in love with a mere mortal. 

One afternoon, seeing Orion swimming far out at sea, he challenged his sister to hit what appeared to be no more than a dot among the waves. "Goddess of hunting you may be," he taunted her, "but I wager you could not hit that faint, dark object there on the horizon." Not realizing that this was Orion, Diana took dead aim with her bow and arrow and shot him. 

Later, when Orion's body washed up on the shore, she saw what she had done. Inconsolable, she placed his body in her chariot and drove to where the night was darkest and placed him into the sky — and suddenly the heavens were bright with stars. Diana also placed Orion's hunting dogs to closely follow him and marked each with a brilliant star. Her grief also explains why the face of the moon, although so bright, appears so sad and cold.

The belt stars

The thing that makes Orion so unique among all the constellations is his belt of three, second magnitude stars. The trio — from lower-left to upper-right — are Alnitak, Alnilam and Mintaka. Many astronomy books refer to them as straight, bright and compact. 

Certainly, they are bright and compact (extending across just 3 degrees of sky), but they're not exactly straight. The middle star, Alnilam appears to ever-so-slightly sag compared to its companion stars that flank it. 

Extending an imaginary line through the belt to the south and east will take you to the brightest star in the sky, blue-white Sirius, the Dog Star. Going in the opposite direction takes you to the V-shaped face of the Taurus constellation, the Bull, with orange Aldebaran marking the bull's angry eye.

A tale of two stars

As we have previously noted, Orion contains two of the brightest stars in the sky. Blue-white Rigel (the 'Left Leg of the Giant'), ranks seventh in terms of brightness rankings at magnitude +0.2. From mid-northern latitudes, Rigel when at its highest point in the southern sky is about at the same altitude above the horizon as Polaris, located diametrically opposite to it in the northern sky.

Located roughly 860 light-years away, Rigel is considered to be the most luminous star within 1,000 light-years of the sun. It's a star literally burning the candle at both ends, shining at the prime of its life. It's a true supergiant: a blazing white-hot star of intense brilliance and dazzling beauty, shining with a luminosity estimated to be roughly 120,000 times that of our sun. 

Rigel is marginally brighter than the bright star marking the opposite side of Orion's extremities, Betelgeuse ('The Armpit of the Giant'). And yet, Betelgeuse seems to attract more attention because, in contrast, it shines with a cool, dull ruddy hue and is located 550 light-years away. 

Recall that Betelgeuse was making headlines a couple of years ago because it had declined in brightness to such a degree that at one point it appeared to be shining at only half of its normal brightness (magnitude +1.6). It is an irregular pulsating supergiant star, nearing the end of its life and as such, it expands and contracts spasmodically and has been seen to get a dim as magnitude +1.1 to as bright as -0.1, brighter than the stars Rigel or nearby Capella.

The stellar incubator

But the true showpiece in Orion that continues to astound even veteran observers can be found hanging directly below Orion's Belt, a trio of fainter stars, Orion's sword, the middle of which appears to have a fuzziness surrounding it. But it is a telescopic view of that fuzz that will reveal a greenish-gray fan of nebulosity known as M42, the Great Orion Nebula.

Here you will find Theta1 (θ1) Orionis, better known as the Trapezium, four tiny bright stars in the heart of M42 that power the nebula. The light of the Orion Nebula is largely fluorescence, produced by the strong ultraviolet radiation from the high-temperature components of the Trapezium. 

Located at a distance of 1,340 light-years from Earth, it is so large that it would take a beam of light 24 years to pass from one side of it to the other. In this time it would be traveling 11 million miles (17.6 million km) every minute of those 24 years. 

Astrophysicists now believe that Orion Nebula is a stellar incubator; the primeval chaos from which star formation is presently underway. It is here where new stars are being born. Stars that will blow away their excess gaseous material when they fully radiate all of their energy, ultimately to shine in tomorrow's sky for future generations to admire. 

Truly, there is magnificence and excitement in the region that we know as Orion. One of the wonders of the nighttime sky.

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, the Farmers' Almanac and other publications. Follow us on Twitter @Spacedotcom and on Facebook

The constellations in the night sky are connected to myth and legend, as well as the unscientific concepts of astrology. But they also have held importance and usefulness to science and exploration throughout history and still today.

Stars in the universe are scattered across a vast, three-dimensional space. When we look up from the surface of our planet, however, humans have historically observed constellations: two-dimensional pictures and shapes connecting the stars in the sky to stories from cultures around the globe. 

In addition to their cultural significance, constellations have also been important instruments that once marked the passage of time and the seasons. Today, constellations continue to be valuable tools to orient astronomers and stargazers in the night sky. 

One constellation tradition is the western zodiac, which is made up of 12 constellations: Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius and Pisces.

Constellations of the Night Sky: Famous Star Patterns Explained (Images)

The zodiac constellations

As Earth rotates, the sun, moon and planets seem to move generally along a set path through the sky, called the ecliptic. 

The 13 constellations in the path of the ecliptic are:

• Capricorn
• Aquarius
• Pisces
• Aries
• Taurus
• Gemini
• Cancer
• Leo
• Virgo
• Libra
• Scorpio
• Ophiuchus
• Sagittarius

Astrologers use 12 of these constellations to roughly correspond with the signs of the zodiac to make predictions. (The 13th, Ophiuchus, it omitted because when the signs were first described, the stars were not in exactly the same position as they are today.) 

Today, the astrological signs differ from these constellations, bearing only a loose reference to one another. The sign of Pisces, for instance, currently corresponds to the rise of the constellation of Aquarius. 

Read more: How the constellations got their names

What is a constellation?

From Earth, stars appear to move across the sky on a regular schedule. That appearance of star movement actually has more to do with the rotation of Earth than the movements of stars themselves. 

Similar to how our sun looks like it's moving across the sky when it's really our planet rotating as it orbits the sun, constellations appear to be rotating across the sky when that movement is really due to our changing viewpoint. 

Read more: Space junk is blocking our view of the stars

Although we're looking at stars across vast expanses of three-dimensional space, the arrangement we see looks two-dimensional. But stars that seem to be right next to each other in a constellation may in fact be hundreds of light-years apart. 

For example, in the well-known constellation Orion, the nearest star to us is Bellatrix, a bit more than 200 light-years from Earth. But the farthest star in that constellation is Alnilam, which is about 1,300 light-years away. But from our viewpoint on Earth, they look like nearby neighbors.

Orion isn't one of the zodiac constellations, though. Those constellations are defined mostly by their position on the ecliptic, an imaginary or projected line in the sky that marks the perceived path of the sun (as well as the rough paths of the planets and the moon, which are all more or less on the same plane) over the course of a year on Earth. 

The path of the ecliptic passes through 13 of the 88 constellations officially recognized by the International Astronomical Union (IAU) since 1929. Just 12 of those constellations make up the western zodiac.

History of the western zodiac

Most of the constellations in the Northern Hemisphere's skies bear Greek and Roman names. According to Encyclopedia Britannica, that is thanks in part to the Almagest, an influential catalog of stars and constellations created by the ancient mathematician Claudius Ptolemy in the second century. 

However, people were mapping the sky long before these names took hold. Ancient China, Sumeria in the Middle East and Egypt each had their own star maps, for example. According to a 2017 paper from the journal of the American Philosophical Society, many of the Greek constellations that we consider to be the Western zodiac today were adopted from Babylonian astronomers. They referred to "The Twins," "The Lion" and "The Crab" thousands of years ago, which are the same constellations we (and the ancient Greeks) know as Gemini, Leo and Cancer, respectively. 

Astrology was once considered part of the science of astronomy. In fact, the famous astronomer Johannes Kepler was considered an astrologer during his life in the 1600s, according to Time magazine. 

Now, however, astrology is commonly considered a pseudoscience. No evidence has been found for the predictive power of astrological predictions based on the zodiac, as demonstrated in this 1985 paper from the journal Nature.

How are the zodiac constellations used today?

In science:

The IAU's 88 constellations, which include all 12 of the zodiac constellations, are still relevant to researchers today. Astronomers can use those markers to explain what parts of the sky are part of their work, or orient themselves to find objects they have seen in space. 

The Morehead Planetarium also recommends using constellations as a reference point to spot faster-moving planets. For casual skywatchers, the zodiac constellations are recognizable because they have a story and shape associated with them. When a planet appears as a bright object in a constellation, watchers can spot that one of the "stars" is out of place and might actually be Mars, Jupiter or Venus instead. 

Similarly, constellations can be used to describe where a meteor shower might appear in the sky, or where a comet might come into view. 

Related: Try "star hopping" to use constellations as guides to find celestial events

In navigation:

Astronauts still learn star navigation, according to NASA's Space Place. It's a backup to computerized navigation systems, but it's a good backup: Seafarers and explorers used stars and constellations to navigate for thousands of years. 

Even autonomous spacecraft, sent to explore far from Earth, can use constellations in their star maps to navigate. 

As inspiration: 

Throughout history, humans around the planet found the stars useful for timing harvests and plantings, but they also used constellations to tell stories and find meaning. 

Now, planetariums and skywatching programs retell those stories to capture attention, spark curiosity and keep the ancient history of space exploration alive. 

Additional resources

• Learn to navigate with the stars using this guide from My Open Country.
• Check out an unofficial set of constellations detected by the Fermi telescope. These newly discovered clusters of gamma-ray objects include constellations named after Godzilla, the Hulk and Albert Einstein.
• Cultures around the world came up with many of the same constellations. A new paper described in Science News for Students explains why.

Amid concern from NASA, SpaceX says it has "significant resources" to exceed best practices with Starlink when it comes to sustainability and safety.

In an update published to the company website Feb. 22, SpaceX outlined its sustainability and safety protocol for its Starlink internet satellites on Monday (Feb. 28), as the company seeks to add tens of thousands more of the probes to its fast-growing megaconstellation. 

This update by SpaceX comes amidst recent concerns raised by NASA about the impact of more Starlink satellites. NASA's concern follows earlier criticisms of  Starlink Internet satellites for accelerating the rate of near-collisions in space, including to the International Space Station, and for interfering with astronomy observations due to their brightness. SpaceX addressed the first concern (the collisions and debris) in detail with this new outline.

Related: SpaceX's Starlink satellite megaconstellation launches in photos

In this new statement, SpaceX promises a commitment for "a safe orbital environment, protecting human spaceflight, and ensuring the environment is kept sustainable for future missions to Earth orbit and beyond."

The lengthy update includes SpaceX's plan of approach for current and future Starlink launches, including high maneuverability, open data sharing with other space companies, agencies and authorities, and an in-space collision avoidance system to be used as a last resort.

In SpaceX's words, these are the company's key practices for Starlink:

• Designing and building highly reliable, maneuverable satellites that have demonstrated reliability of greater than 99%;
• Operating at low altitudes (below 600 km [372 miles]) to ensure no persistent debris, even in the unlikely event a satellite fails on orbit;
• Inserting satellites at an especially low altitude to verify health prior to raising into their on-station/operational orbit;
• Transparently sharing orbital information with other satellite owners/operators;
• Developed an advanced collision avoidance system to take effective action when encounter risks exceed safe thresholds.

For this constellation of satellites, SpaceX is leaning on advanced technologies such as inter-satellite optical (or laser) communications to make these best practices possible, the company said in the update. SpaceX additionally urged other operators "to join us" in practices such as sharing orbital data and updating key government stakeholders, especially including the Federal Communications Commission (FCC) that governs telecommunications activities in orbit.

"SpaceX continues to innovate to accelerate space technologies, and we are currently providing much-needed internet connectivity to people all over the globe, including underserved and remote parts of the world, with our Starlink constellation," SpaceX noted.

The company pointed to other factors that make Starlink a highly adaptable system, in SpaceX's eyes, including a low rate of individual satellite failure (1%), a commitment to deorbit satellites deemed at risk of failure and special shields and battery equipment to reduce micrometeorites or battery failures from causing catastrophic issues. Further, within these practices, all satellites are deorbited within four weeks of ending their operational lifetime.

On Feb. 3, SpaceX executed a launch in which the satellites on board were destroyed due to solar activity temporarily increasing the density of the Earth's atmosphere. 

SpaceX argued that by placing the satellites into a low orbit, rare situations like this  allow the satellites to be "quickly and actively deorbited using its thruster, or passively by atmospheric drag." (The company is also asking that the FCC change its standards for deorbiting from 25 years to a much faster timeline, to reduce the risk of orbital debris.)

The company also pointed to data transparency practices it would like other operators to do, such as sharing orbital parameters on Space-Track.org and providing "routine system health reports" to the FCC that include recent orbital maneuvers to reduce collision risk.

SpaceX acknowledged that its satellites have come close to major hardware, including the ISS and the Chinese space station Tiangong, but said its collision risk system has been checked out with NASA's Conjunction Assessment and Risk Analysis (CARA) program under a Space Act Agreement with NASA.

"We work directly with NASA and receive ISS maneuver plans to stay clear of their current and planned trajectory including burns," SpaceX wrote. "China does not publish planned maneuvers, but we still make every effort to avoid their station with ISS-equivalent clearance based on publicly available ephemerides [orbit information]."

Nevertheless, NASA has raised concerns about SpaceX's new Starlink satellites. The agency has "concerns with the potential for a significant increase in the frequency of conjunction events and possible impacts to NASA’s science and human spaceflight missions," the agency stated in a letter which was submitted to the FCC in February as SpaceX requested permission to add 30,000 more Starlink internet satellites into orbit as part of a "Gen 2" Starlink system.

"NASA wants to ensure that the deployment of the Starlink Gen 2 system is conducted prudently," the agency added, "in a manner that supports spaceflight safety and the long-term sustainability of the space environment." The decision to approve SpaceX's Gen 2 system is still with the FCC.

Follow Elizabeth Howell on Twitter @howellspace. Follow us on Twitter @Spacedotcom or Facebook. 

I once received an interesting inquiry from a woman who wanted to know the meaning of the terms "morning stars" and "evening stars."  She wrote: 

"I mean, they're not stars … they're planets, right? So why do we call them stars? And is a 'morning star' only visible in the morning, like at the crack of dawn, or at other times as well? Hope you can clear this up for me because I'm totally confused!"

Here is an explanation for what qualifies as a "morning star" and an "evening star."

Related: The brightest planets in the night sky: How to see them (and when)

It began with Venus

Originally, the terms "morning star" and "evening star" applied only to the brightest planet of all, Venus. It is far more dazzling than any of the actual stars in the sky and does not appear to twinkle. Instead, it glows with a steady, silvery light. The fact that Venus was a wandering star soon became obvious to ancient skywatchers, who noticed its shifting back and forth from the early hours of the eastern morning sky to the western sky in the early evening. Nicolas Camille Flammarion, a noted French astronomer in the late 19th and early 20th century, referred to Venus as "The Shepherd's Star." I myself like to refer to Venus as the "night light of the sky." So, one can readily understand the origin of the terms evening and "morning star" if we only considered Venus. 

Of course, Venus is not the only wandering "star" in the sky; there are four others that are also visible to the unaided eye (five, if you include Uranus, which is barely perceptible without any optical aid on dark, clear nights). The difference is that, with the possible exception of Jupiter and, on rare occasions, Mars, none of the others stands out in the same manner as Venus. Nonetheless, somewhere in the distant past, "morning star" and "evening star" became plural in order to account for the four other planets.  

When an evening star is branded as a morning star

It is quite understandable to see why the definitions of "morning star" and "evening star" can be confusing. Sometimes, for instance, we might see a bright planet like Jupiter shining brilliantly just above the eastern horizon in the evening. Within an hour or so, it has climbed well up into the eastern sky. "Ah!" you might say, "Jupiter certainly makes for a fine evening star." As the night wears on, Jupiter attains its highest point in the southern sky after midnight, and it will still be visible, sinking in the western sky at dawn. The giant planet is thus ideally situated for observations of its changing cloud bands and four big Galilean moons for much of the night.

The fact that Jupiter is already above the horizon during normal evening hours seemingly should qualify it for "evening star" status. But the distinction between these terms is not very precise, for yet, by the same reasoning, it is still considered strictly a "morning star."

How can that be?

Certainly, the "morning star" branding would make more sense if Jupiter were rising closer to, or even after midnight and crosses the southern meridian by sunrise. More on this in just a moment. 

No double-meaning for the inner planets

With Mercury and Venus, however, there is never such ambiguity, since they are never very far from the sun in the sky. Because they orbit the sun more closely than Earth, Mercury and Venus are called "inferior" planets. In fact, in the pre-Christian era, both of these planets had dual identities — two names — as initially it was not realized they alternately appeared on one side of the sun and then the other. Mercury was called "Apollo" when it shone in the mornings and "Hermes" when it appeared in the evening sky; Venus was "Phosphorus" in the morning and "Hesperus" in the evening. We can thank Pythagoras around the 5th century B.C. for pointing out that the latter two objects were really one in the same. 

So, in general, when either of these planets has a western elongation from the sun it is a "morning star"; with an eastern elongation it is an "evening star." When they are aligned more-or-less with the sun as seen from our Earthly perspective, they will make the transition from evening to morning or vice versa:

When Mercury or Venus is passing between the sun and Earth, we say they are at inferior conjunction and go from being categorized as "evening stars" to transitioning to "morning stars." When the alignment is such that they appear roughly on a line beyond the far side of the sun as seen from Earth, we then say that they are in superior conjunction; that is when they make the switch from being considered "morning stars" to "evening stars." 

A celestial racetrack

An interesting analogy is to consider being a spectator at a motor speedway or racetrack and watching a race between two cars. If we consider for a moment that the two cars represent Mercury and Venus, and that the starting point was on that side of the track closest and directly in front of you (with an imaginary sun at the middle of the track), then that could also be considered as the point of inferior conjunction. As the two cars pull away from you and veer off to the right, they would simulate the changing positions of Mercury and Venus as "morning stars"; they would appear speed away to the right (west) of the sun in the sky, and as such would appear to rise before the sun. 

Eventually, the cars would arrive at that point where they would appear to curve around and sweep back to the left. When they reached that point on the far side of the track, but were again directly in front of you, we would consider that to be superior conjunction. Now, the two cars are sweeping around to the left from our perspective, and simulating the changing positions of Mercury and Venus as "evening stars"; they would appear speed away to the left (east) of the sun in the sky, and as such would appear to set after the sun.

Transition at opposition

Things are somewhat different for the planets that orbit the sun beyond our own orbit — the so-called "superior" planets, Mars, Jupiter, Saturn, Uranus and Neptune. In order to differentiate between what qualifies for the branding as a "morning star" versus an "evening star," we would say that during the time frame from when a planet is moving from its conjunction with the sun to just a day prior to its opposition (when it is directly opposite to the sun in the sky) it is considered a "morning star." At opposition, the superior planet in question would be rising when the sun sets and sets as the sun rises. From then on it is branded as an "evening star," rising or already in the sky as daytime ends. 

Still, as we have already seen, the branding of a morning versus evening object might get a bit confusing, particularly in the few weeks leading up to opposition, when a superior planet is rising only an hour or two after sunset and is already well-placed for observation at a convenient evening hour and yet is still considered a "morning" star. This is particularly true during the wintertime when the sun sets rather early in the evening. If a planet like Mars, does not emerge above the eastern horizon until an hour or two after sunset, it will still be branded as a "morning star" even though it is shining brightly for all to see during convenient prime-time evening hours!

A change in venue

Incidentally, if we try to use our race track analogy in the case of the superior planets, we'd have to make an important change, because unlike the inferior/inner planets, which are racing around the sun more rapidly than Earth, our home planet in contrast, is moving more rapidly around the sun compared to the superior/outer planets. 

So rather than being a spectator at the race, we would need to become a participant! 

On the race track, our car would always be chasing, overtaking and ultimately leaving the slower cars that are representing the superior planets behind. They would all be positioned on the outside of the track, to our right. And because of this perspective, when a superior planet is on the far side of the track as seen by us (and becomes aligned with the sun), the more rapid motion of our Earth causes the slower planet to appear to drop back toward the sun in our evening sky until it arrives at solar conjunction. Then several weeks later it emerges back into view in the morning sky, rising before sunrise. 

Interestingly, when they are passing behind the sun, the inferior planets appear to move from right to left, transitioning from the morning to the evening sky. But for the superior planets, it is just the opposite: They appear to move from left to right when making the transition from the evening into the morning sky. 

Additional reading and resources

There are scores of excellent books and publications about the planets. For those who want to study the subject further, here is a short list of some of them:

"A Field Guide to the Stars and Planets," 4th ed., by Donald H. Mensel and Jay M. Pasachoff (Houghton Mifflin, 1999)

"Observer's Handbook" (Royal Astronomical Society of Canada, Annual Publication)

"Skywatching" by David H. Levy (The Nature Company Guides/Time-Life Books, 1995)

"Stars" by Herbert S. Zim and Robert H. Baker (Western Publishing Co., Inc 1975)

"Stars & Planets" by Ian Ridpath and Wil Tirion (Princeton University Press, 2008)

"The Planets" by Nirmala Nataraj and Bill Nye (Chronicle Books, 2017)

"The Planets: The Definitive Visual Guide to our Solar System" by Robert Dinwiddie and 7 others (Dorling Kindersley Limited/DK, 2014)

Bibliography

• "Popular astronomy – A General Description of the Heavens" by Camille Flammarion, translated from the French with the author's sanction by J. Ellard Gore (New York D. Appleton and Company 1894). Page 331.
• "How Did Mercury Get Its Name?" Universe Today. https://www.universetoday.com/66432/how-did-mercury-get-its-name/ 

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, the Farmers' Almanac and other publications. Follow us on Twitter @Spacedotcom and on Facebook.

Over the years, many have asked me to recommend books to help them in their study of the stars and constellations. 

In this column, I'll provide reviews of three books that I consulted during my formative years in the hobby. 

All three proved most valuable to me for my then-burgeoning interest in astronomy and I'm sure the same would hold true for most anyone who will take the time to use them today. 

1. "Stars" by Herbert S. Zim and Robert H. Baker

A Golden Guide from St. Martin's Press, 2001
160 pages

This was my very first astronomy book, which I received at the age of 8, and is in my opinion still among the very best as an introduction to not only the stars and constellations, but astronomy as well. "Stars," first published in 1951, is one of a series of pocket Golden Guides on nature and physical science, which has been updated over the years, most recently in 2001.

The book was written by naturalist Herbert S. Zim (1909-1994) and astronomer Robert H. Baker (1883-1964). The latter was once head of the University of Illinois Department of Astronomy and was also the author of what is still considered a classic among college textbooks on astronomy ("Introduction to Astronomy," Van Nostrand publishers). Baker also authored two other excellent books, "When the Stars Come Out" and "Introducing the Constellations," both published by Viking Press.  

Augmenting the text by Zim and Baker are 150 beautiful color paintings rendered by James Gordon Irving (1913-2012), whose paintings were exhibited at the American Museum of Natural History and the National Audubon Society in New York City. 

This book was an immense help to me in identifying the brightest stars and constellations at a very young age. There are 23 maps that show constellations as lines connecting the principal naked-eye stars, traced within pictorial images of what each star pattern supposedly represented. 

Additional charts and diagrams help, although the four seasonal star maps which are used to locate these stars are a bit confusing. 

Nonetheless, the book contains a lot of valuable information and observing tips regarding the sun, moon, planets and stars, as well explanations for unusual atmospheric phenomena such as the sun's red color at sunrise and sunset, rainbows, lunar and solar haloes as well as the aurora borealis or northern lights.

If you're just starting out with astronomy as a hobby, this little handbook is perfect for anyone who wants to enjoy the wonders of the night sky. Written in easy-to-read language, it is ideal for use at home, as well as to take along on a vacation or a camping trip. 

2. "The Stars: A New Way to See Them" by H.A. Rey

Houghton Mifflin Company, Boston, 2008
160 pages

As I noted for the Golden Guide's "Stars," there were pictorial images of the person, creature or object that a constellation represented. But 70 years ago, Hans Augusto Rey (1898-1977) devised a different methodology of identifying the constellations using his own stick-figure star patterns and introducing them in "The Stars: A New Way to See Them," a guidebook published in 1952 and revised several times ever since. Indeed, this book has been extremely popular, going through a number of printings and selling hundreds of thousands of copies. Many people swear by Rey's patterns, claiming they are easier to learn and see in the sky. 

I first came across a copy of Rey's book when I was 10 years old and was immediately intrigued by a number of his clever creations, such as the Gemini twins holding hands (most often used in advertising the book). 

There are, however, many legends and mythological stories that date back thousands of years explaining the creation of the constellations. But for his book, Rey for the most part has ignored these ancient legends and performed radical surgery on virtually all of the constellations, seemingly to conform solely to his ideas as to what a particular star picture should look like. 

It makes one wonder who had the more fertile imagination: those cultures who actually invented the constellations all those many centuries ago, or Rey himself? 

Some examples: 

For Ursa Major, Rey made the end of the Big Dipper's handle — long regarded in mythology as the tail of the Great Bear — into its nose! 

In the case of Cetus, the whale, he turned that mammal's tail into its face, even though the star Deneb Kaitos is located there; Arabic for the southern tail of Cetus. 

Hercules has always been considered a kneeling giant with its brightest star, Rasalgethi marking "the head of the kneeler." But Rey turns Hercules into a man wielding a club with Rasalgethi marking his left foot. 

As for Virgo, her brightest star, Spica, is supposed to mark a spike of wheat held in her hand. But according to Rey, Spica is the Virgin's "brightest jewel," positioned he writes, "on an unusual spot" (her derrière).

And then in those cases where some constellations came reasonably close to depicting what they represented, Rey could not leave well enough alone. In some cases, like with Pegasus, the flying horse and Taurus, the bull, his stick-figure renditions were decidedly forced and not really all that obvious, looking more like abstract art — something resembling sketches by Pablo Picasso. 

Despite these drawbacks, I still very much like "The Stars: A New Way to See Them" as an easy-to-comprehend work that, among other things, explains to the novice how not mistake a planet for a star and cites the reasons for planetary movements. The speed of light and light-years are explained on a totally non-technical level, and overall, this book does an admirable job in explaining some of the complicated concepts about the night sky and what it contains. 

And I would even regard Rey's abstract patterns as a challenge to those who wish to hone their star-finding skills.

3. "A Primer for Star-Gazers" by Henry M. Neely

Harper and Row, New York, 1970
334 pages

From time to time, I have mentioned Henry M. Neely (1877-1963) who, after a distinguished career in radio, took up astronomy relatively late in life. He was a longtime lecturer at New York's Hayden Planetarium and became one of the nation's leading popularizers of astronomy. Sadly, he died before I had a chance to hear any of his lectures, but Neely wanted everyone to share in the beauty and splendor of the heavens. His 1946 book "A Primer for Star-Gazers" was last updated in 1970 and remains a powerful yet simple tool in the study of the stars and constellations. 

Unfortunately, revised distances for many stellar and deep-sky objects dating back to the book's first edition were never updated. Thus, on page 195, the Andromeda galaxy is listed as being 750,000 light-years away, whereas current figures are more than three times as great. But the author's aim in this book is to help you find the stars, not to fill you with facts and figures. Neely visualized his reader as wanting simply to recognize the principal stars and constellations without making a real study of astronomy. 

"A Primer" follows this philosophy from cover to cover. It contains 96 sky maps all drawn by Neely, with all navigational stars indicated as such, and with a unique calendar that tells which maps to use for prominent objects. This book proves itself to be an elaborate yet easy-to-use star finder. Follow the instructions in Chapter 5 ("How to Use This Book"), then go outside, select the proper map for the evening, rotate the book as directed, look at the page, then at the sky, and there should be the desired constellation. Phonetic spellings of star and constellation names are given next to the regular spellings. The Big and Little Dippers and Cassiopeia's "W" are chosen as the first groups to recognize, for later use in locating others. The book provides excellent descriptions of how to find each constellation and notable objects within it. 

Neely had a predilection for turning some classical star patterns into geometric shapes. Thus, we are introduced to "The Kite in Auriga," "The Long Wedge of Gemini," "The Great Virgo Triangle," and depicting Hercules as yet another kite ... but also with a tail. 

He may well have been the very first to turn Sagittarius from an archer into a teapot (Chapter XXIV) and on page 187, he incorporated the stars of Cygnus, Lyra and Aquila into a baseball game in the sky. Deneb was home plate; Epsilon Cygni, first base; Eta, second base; Delta, third base; and Sadr, the pitcher's mound. Left fielder Vega and center fielder Albireo are running to catch a fly ball in left-center field, while Altair, the right fielder, watches. Such imaginative variants of constellations are quite effective in teaching the sky, especially to youngsters.

The only negative for this book that I would register is in Chapter 16, where Neely turns the constellations of Andromeda, Perseus, Aries and Triangulum into his own creation: The Yacht. 

I must tell you that in all my years of skywatching, I have never been able to visualize it, even though Neely claims that, "... it does not require nearly as great a stretch of the imagination as many of the traditional figures allegedly seen by ancient stargazers." 

With all due respect to Neely, I disagree! 

Like some of Rey's creations, The Yacht is a highly abstract star pattern. Good luck with it!

Overall, however, this fine book should make the task of a beginner to locate all the stars and constellations noted in this text quite easy and, as Henry Neely himself would like it to be, most enjoyable. 

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, the Farmers' Almanac and other publications. Follow us on Twitter @Spacedotcom and on Facebook.

The Snow Moon will reach its peak today (Feb. 16) and join a cluster of planets lighting up the morning sky.

The full moon, known as the Snow Moon, will be at its brightest at 11:57 a.m. EST (1657 GMT), though it will appear nearly full both the night before and the night after. And the moon isn't the only excitement in the night sky; if you look carefully by the full moon tonight you will see the bright star Regulus in the constellation Leo, the lion.

And don't forget to look up in the early morning sky as a few planets will also make an appearance.

Related: February full moon 2022: The 'Snow Moon' is accompanied by predawn planets

A few planets will accompany the moon in the early morning today. 

For those in the eastern U.S., Venus rises at approximately 4:20 a.m. local time in New York City (0920 GMT) today and the planet will be 22 degrees above the horizon by sunrise. Mars comes up a little later, at 4:48 a.m. EDT (0948 GMT) and you should be able to spot fleeing Mercury as it is at its greatest distance, or elongation, west of the sun. Yet another planet, Jupiter, will also be visible for a short window before sunset tonight.

While those planets are rising in the east, the full moon will be setting in the west. In New York City, for example, the moon will set at 7:11 a.m. local time and rise again tonight at 5:32 p.m. local time. (You can find out exactly what time the moon will rise and set at any location using Time and Date's moon calculator.)

The Snow Moon is one of many monikers by which February's full moon is recognized. While the moon goes by different names in different cultures, the Maine Farmers' Almanac began publishing the moon names given and known by Native American tribes in the 1930s.

The Snow Moon (also called the Storm Moon) is a name that stems from the Algonquin tribe "because of the heavy snows that fall in this season," according to NASA.

If you're looking for binoculars or a telescope to see the moon in the night sky, check out our guide for the best binocular deals and the best telescope deals now. If you need equipment to capture the moment, consider our guides for the best cameras for astrophotography and the best lenses for astrophotography to make sure you're ready for the next moon sighting.

Follow Elizabeth Howell on Twitter @howellspace. Follow us on Twitter @Spacedotcom or Facebook. 

A new luxury watch closely tracks the phases of the moon in an elegant format — and comes with a hefty price tag.

On Feb. 1, the Swiss luxury watchmaking company Ulysse Nardin launched a new wristwatch called "Blast Moonstruck," which aims to show how the moon, the sun and other celestial movements appear from the Earth's perspective. It has a limited-edition run, so if you're willing to spend $79,100 on this watch, the company urges you to buy soon.

Besides moon phases, the watch also tracks the moon's rotation, the (apparent) movement of the sun around the Earth, and the tides. The wristwatch glance at celestial movements is perfect for beginning astronomers, the company says.

Related: Omega debuts next generation of NASA-qualified Speedmaster moonwatches

"I am delighted that my watches and astronomical clocks enable people to think about their position in the universe, and perhaps realize that we are not the center of the world," watchmaker Ludwig Oechslin said in a company statement.

Oeschlin is known for producing a series of astronomical wristwatches in the 1980s for the luxury market. This new watch is distinctive from older watches with its focus on having readouts understandable by non-specialists, the company says.

The 45-millimeter watch features a black ceramic and black titanium finish, with options of alligator skin, velvet or rubber straps in black to complement the display.

The moon phase indicator, which is the heart of the watch, makes a complete rotation every 29 days, 12 hours, 41 minutes and 9.3 seconds in line with the duration of the moon's orbit with respect to the line joining the sun and the Earth. (This is also called a "lunation.")

Moonwatchers will also enjoy seeing exactly where both the sun and the moon are located above the Earth, from our perspective. This will especially be important during eclipses of the sun and the moon, which happen during celestial alignments of those two worlds with the Earth.

But if you're like most of us and need to find moon phases in a more affordable format, you can consult Space.com's moon phase calendar and our monthly discussions of the full moon, like February's Snow Moon.

Follow Elizabeth Howell on Twitter @howellspace. Follow us on Twitter @Spacedotcom or Facebook. 

The full moon of February, known as the Snow Moon, will reach peak illumination in the eastern U.S. at 8:53 a.m. EST (1353 GMT) on Feb. 12, three days after it occults Mars.

The full moon occurs when the moon is directly opposite the sun from Earth's perspective. Most of the time, it is fully illuminated by sunlight. Occasionally, the moon's orbit carries it into Earth's shadow, causing a lunar eclipse. However, February's full moon will bypass Earth's shadow because the moon's orbit is tilted about five degrees relative to Earth's orbital plane, preventing perfect alignment between the sun, Earth, and moon.

A full moon's timing depends on one's time zone; the moon reaches full phase after the moon is above the horizon in Africa and Asia; for example, the full moon is at 6:53 p.m. local time in Tashkent, Uzbekistan, five hours ahead of Greenwich Mean Time, and moonrise is at 5:39 p.m. As one moves further east the moon is higher above the horizon as it reaches full phase. In Singapore, the full moon is at 9:53 p.m. local time and moonrise is at 7:16 p.m. local time. In the other direction, observers in Hawaii will see the full moon at 3:53 a.m. local time, well before the moon sets at 7:20 a.m. In New York, the moon rises at 5:40 p.m. local time, sunset that day is at 5:27 p.m.; for skywatchers in the continental U.S. the moment when the moon reaches full phase occurs when it is below the horizon.

On February 9 the moon occults Mars. The occultation will be visible across the far northern parts of North America, northern Asia and Europe; in other places, the moon will make a close pass to the planet. One of the southernmost places Mars' disappearance will be visible from, just as the moon sets, is Hong Kong; the moon will be hugging the horizon. Mars disappears behind the moon there at 5:03 a.m. local time on Feb. 10; but at that point, the moon will be only about 2 degrees in altitude; the moon sets there at 5:15 a.m., according to data from the International Occultation Timing Association.

Observing prospects are much better as one moves far north; to catch the entire occultation while both the moon and Mars are above the horizon one must be at least at the latitudes of mainland China; the further north one is the higher both will be in the sky at the moment of Occultation. In Beijing, for example, the occultation starts at 4:30 a.m. local time with the moon about 14 degrees above the northwestern horizon. Mars emerges from behind the moon at 5:20 a.m. just as the moon is setting.

Other Asian cities where the occultation will be visible include Almaty, Kazakhstan, where the occultation begins at 1:41 a.m. local time on Feb. 10, with Mars re-emerging at 1:58 a.m. In Ulaanbaatar, Mongolia, it starts at 2:09 a.m. on Feb. 10 and ends at 3:13 a.m.

In Europe one can see the event from Iceland, where Mars touches the moon at 6:30 p.m. local time and reappears at 7:21 p.m. local time; the moon will be in the eastern sky about 55 degrees high when it starts.

Other European locations include Helsinki, from 9:25 p.m. local time. Mars will pass behind the southern side of the moon (closer to the horizon) for just eight minutes, emerging at 9:33 p.m. The moon will be about 55 degrees high in the southeast. In Bergen, Norway, the occultation starts at 7:58 p.m. Central European Time and ends at 8:17 p.m. In Umea, Sweden Mars touches the western side of the moon at 8:05 p.m. and emerges at 8:45 p.m. Oslo and Stockholm are both just a bit too far south to catch the occultation; in both cases, the moon will appear to pass just above Mars in a close conjunction.

Visible planets 

By mid-February, at the latitude of New York City, the sky will be fully dark at about 7 p.m. The moon will be almost due east, about 15 degrees above the horizon, and Mars, in the days post-occultation, will high be above it; at about 56 degrees. In New York City, the Red Planet sets at 5:24 a.m. Feb. 13.

Jupiter is high in the south, above the constellation Orion, the Hunter. By 7 p.m. the planet is a full 70 degrees high; in New York, it transits at 7:02 p.m. Jupiter sets at 2:25 a.m. local time on Feb. 13. In the west, Venus, the brightest planet and third brightest object in the sky after the sun and moon, is 17 degrees above the western horizon. By 7 p.m. Saturn is very close to the horizon; the ringed planet sets at 7:26 p.m. in New York. Earlier in the evening, just after sunset at 5:27 p.m., one can see it below Venus — though it will take until about 6 p.m. for th sky to get dark enough to see Saturn.

Constellations 

By February the bright winter constellations are out by the early evening. For Northern Hemisphere mid-latitude observers, Orion is visible the first half of the night, starting the evening high in the southeast by 7 p.m. Near Orion are Taurus and Gemini, with Taurus on the right and above Orion and Gemini to the left and above it.

To the southeast (left and below) of Orion is Canis Major, the Big Dog, home to Sirius, the sky's brightest star. Orion, especially, is so bright that the three stars of the Belt are still visible even in urban areas. In the mid-southern latitudes, the sky gets darker later as it is still the summertime, but by 10 p.m. when the moon is in the northeast, the Southern Cross will rise in the southeast, about 25 degrees high from the latitude of Valparaiso, Chile. The sky is "upside down" from the Southern Hemisphere, so Orion is above the northern rather than the southern horizon by 10 p.m., and Sirius is above, rather than below it. Looking towards the south, about 70 degrees high is Canopus, notable as it is also one of the brightest stars.

Moon Legends 

While the Old Farmer's Almanac refers to the February full moon as the Snow Moon, Native nations in the Americas had several different traditional names for it. According to the Ontario Native Literacy Project, the Ojibwe (or Anishinaabe) people called February's full moon Mikwa Giizis, the Bear Moon. The Tlingit of the Pacific Northwest calls the February full moon S'eek Dís, or Black Bear Moon, while the Haida called it Hlgit'ún Kungáay, or "Goose moon," according to the Tlingit Moon and Tide Teaching Resource published by the University of Alaska at Fairbanks. In the southeast of what is now the United States the Cherokee called the second lunation of the year the Bone Moon.

In the southern hemisphere, February is during the summer, and the Māori of New Zealand described the lunar month in February to March (as measured between the successive new moons, with the full moon halfway between) as Poutū-te-rangi or "the crops are now harvested," according to the Encyclopedia of New Zealand.

In China, the traditional lunar calendar calls the February lunation the first month, Zhēngyuè. The start of the month is when the Chinese Lunar New Year is celebrated; the full moon falls in the middle of the month and is when many Chinese communities celebrate the Lantern Festival. During the festival people make paper lanterns and sometimes write riddles on them; it's often a high point of Chinese New Year festivities.

Arcturus is a red giant star in the Northern Hemisphere of Earth's sky and the brightest star in the constellation Boötes (the herdsman). Arcturus is also among the brightest stars that can be seen from Earth. Astronomers say Arcturus will end up as a white dwarf at the end of its life.

The name Artcurus comes from the Greek meaning "keeper or guardian of the bear", which refers to its position adjacent to the tail of the constellation Ursa Major (the Great Bear). 

Locating Arcturus

Arcturus can be found around 37 light-years away from Earth and is the 4th brightest star in the night sky. 

The easiest way to spot Arcturus is by following the curve of the "handle" of the Big Dipper . A simple way to remember how to find the star is to recall the famous phrase "Follow the arc to Arcturus and then speed on to Spica." The latter part of that phrase refers to the bright star Spica, which is actually a binary star. 

Arcturus's location is:

• Right ascension: 14 hours, 15 minutes, 39.7 seconds
• Declination: +19 degrees, 10 minutes, 57 seconds

Chicago World's Fair

Organizers for the Chicago World's Fair in 1933 were searching for a memorable way to open their exhibit. The previous world's fair in the city had occurred 40 years earlier, in 1893. Because at the time, Arcturus was believed to be about 40 light-years away from Earth, the fair's organizers hit upon the idea of using the star's light as a part of the new exhibition and as a way to commemorate the previous Chicago World's Fair.

At 9:15 p.m. Central Time on May 27, 1933, telescopes focused the star's light on several photoelectric cells. The electric current from the star-powered photo cells was used to flip a switch that turned on the floodlights at the exhibition grounds.

Years later, measurements refined the distance to Arcturus as 37 light-years away from Earth. So, the light that was used at the Chicago's World Fair actually began its journey to Earth in 1896, not in 1893.

Modern understanding of Arcturus

Today, astronomers know that Arcturus packs a lot of punch despite being only about 1.5 times the mass of the sun. To the naked eye, Arcturus appears to shine about 113 times more brightly than the sun, according to Jim Kaler, a professor emeritus at the University of Illinois at Urbana-Champaign.

Arcturus, however, has a lower temperature than the sun, which means that a lot of the red giant star's energy is radiated as heat. Once this is accounted for, Arcturus actually releases 215 times more heat than Earth's sun. Arcturus has an apparent magnitude of -0.04 and an absolute magnitude of 0.2. (The brighter the star, the lower its apparent and absolute magnitudes.) The star is in the latter stages of its life. Considered a red giant, Arcturus has stopped fusing hydrogen in its core, as the sun does, and astronomers believe it is now starting to fuse heavier elements such as carbon. 

"Such stars are not expected to have magnetic activity like the sun, but very weak X-ray emission suggests that Arcturus, indeed, is magnetically active and has a hard-to-observe 'buried corona,'" wrote Kaler, referring to the shining shell of a star that is most easily visible when the star's main body is eclipsed.

Once Arcturus exhausts its helium supply, its outer layers will likely bleed off, leaving behind a white dwarf remnant.

Arcturus in fiction

No planets have been found surrounding this star, although science fiction has explored that subject. One early example is David Lindsay's book "A Voyage to Arcturus" (Methuen & Co. Ltd., 1920). The book's protagonist travels to Tormance, a fictional planet that orbits Arcturus.

Arcturus — either the star or a fictional planet with the same name — has also appeared in many other science fiction series, including Isaac Asimov's "Foundation" book series, the "Doctor Who" and "Star Trek" television series, and the movie "Aliens." In "The Hitchhiker's Guide to the Galaxy" universe, a famous phrase goes, "However fast the body travels, the soul travels at the speed of an Arcturan megacamel."

Additional resources

To find out more about constellations and stars, head to the International Astronomical Union. Check out "Constellations: The Story of Space Told Through the 88 Known Star Patterns in the Night Sky" by Govert Schilling and " The Easy Guide to the Night Sky: Discovering the Constellations with Your Eyes and Binoculars" by Richard J. Bartlett for more on observing he night sky. 

Bibliography

James B. Kaler, "Arcturus. In: The Hundred Greatest Stars", Springer, New York, 2002, https://doi.org/10.1007/0-387-21625-1_10 

Cheryl R. Ganz, "The 1933 Chicago World's Fair", University of Illinois Press, 2008. 

Harvard-Smithsonian Center for Astrophysics, "Bootes", Chandra X-ray Observatory, December 2013. 

The International Astronomical Union (IAU) has launched a new center to fight the threat of satellite megaconstellations, which it now describes as worse than urban light pollution. 

The Center for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference will be run jointly by the U.K.-headquartered Square Kilometer Array Observatory organization and the U.S. National Science Foundation's National Optical-Infrared Astronomy Research Laboratory (NOIRLab).

Both of these organizations are dealing firsthand with the fallout of the megaconstellation boom. The next-generation observatories these two institutions are currently developing (the world's largest radio astronomy array built by SKAO on two sites in Australia and South Africa and NOIRLab's Vera C. Rubin Observatory in Chile) will have their observations compromised by the satellite interference, the organizations revealed previously in separate statements.

Speaking at the press briefing announcing the new center, former IAU General Secretary and the center's director Piero Benvenuti said megaconstellations now present a worse threat to astronomy than light pollution. 

Related: Megaconstellations like SpaceX's Starlink will make search for life by world's largest radio telescope difficult

"In the past, the main source of interference was the light pollution produced by the urban illumination, the so-called artificial light at night," Benvenuti said. "But more recently, the impact of the large constellations of communication satellites became a more serious concern because of their ubiquitous invasiveness."

While in the past the remote deserts of Chile, Australia or South Africa could provide a refuge from the world's bright lights and buzzing communication networks, there is nowhere for the astronomers to hide from the thousands of satellites circling the planet. 

"By the end of the decade, more than 5,000 satellites will be above the horizon at any given time," Connie Walker, a scientist at NOIRLab and one of the codirectors of the new center, said in the briefing. "At a typical dark sky observatory location, a few hundred to several thousand of these satellites will be illuminated by the sun."

These satellites, she added, will be detectable even by the smallest optical and infrared telescopes. 

Moreover, the amount of metal orbiting Earth will reflect so much light that the night sky will brighten up enough for the telescopes to notice, making observations of the most distant and dimmest stars and galaxies difficult. 

SKAO, which measures faint radio signals coming from distant stars, galaxies and planets, will be partially blinded in the frequency bands in which these satellites downlink their data, Federico di Vruno, SKAO's radio interference manager and a codirector of the new center, told Space.com in an earlier interview. The search for traces of life, the hunt for exoplanets as well as the study of the most distant universe will all be affected, he said. 

The new center aims to bring together the astronomical community with the megaconstellation operators and regulators to help find solutions to protect ground-based astronomy as the number of satellites circling the planet grows. 

Since 2019, SpaceX has launched over 2,000 of its internet-beaming Starlink satellites, only one-sixth of its envisioned first-generation constellation and a small fraction of the 42,000 satellites it has permission to launch. Its competitor OneWeb plans a constellation of about 2,000 satellites. Other players, including Amazon CEO Jeff Bezos and a Chinese state-backed consortium plan to build megaconstellations as well. 

Astronomers grasped the problem soon after the launch of the first batch of Starlink satellites. While many amateur skywatchers were mesmerized by the "strings of pearls" traveling across the sky after each launch, the professional community understood that major problems were ahead.

Two years later, the IAU called for the establishment of the center. The union also started discussions with the United Nations to protect the pristine night sky as human heritage. 

While some of the approaches to be developed by the new center will focus on software and technical mitigation solutions to be implemented on the side of the observatories, the astronomers also hope that megaconstellation operators will agree to make adjustments on their satellites to reduce the impact. SpaceX has previously trialled two such approaches — the DarkSat and the VisorSat — to reduce the satellite's glow. 

Follow Tereza Pultarova on Twitter @TerezaPultarova. Follow us on Twitter @Spacedotcom and on Facebook.