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Night sky, March 2021: What you can see this month [maps]

A clear night sky offers an ever-changing display of fascinating objects to see — stars, constellations, and bright planets, often the moon, and sometimes special events like meteor showers. Observing the night sky can be done with no special equipment, although a sky map can be very useful. Binoculars or a good beginner telescope will enhance some experiences and bring some otherwise invisible objects into view. You can also use astronomy apps and software to make your observing easier, and use our Satellite Tracker page powered by N2YO.com to find out when to see the International Space Station and other satellites. Below, find out what's up in the night sky tonight (Planets Visible Now, Moon Phases, Observing Highlights This Month) plus other resources (Skywatching Terms, Night Sky Observing Tips and Further Reading).

The night sky is more than just the moon and stars, if you know when and where to look. (Image credit: Karl Tate/SPACE.com)

Monthly skywatching information is provided to Space.com by Chris Vaughan of Starry Night Education, the leader in space science curriculum solutions. Follow Starry Night on Twitter @StarryNightEdu and Chris at @Astrogeoguy.

Editor's note: If you have an amazing skywatching photo you'd like to share for a possible story or image gallery, you can send images and comments in to spacephotos@futurenet.com.

Night Sky Guides:

Calendar of Observing Highlights

Monday, March 1 - Zodiacal Light (after dusk)

(Image credit: Starry Night)

If you live in a location where the sky is free of light pollution, you might be able to spot the Zodiacal Light, which will appear during the two weeks that precede the new moon on Saturday, March 13. After the evening twilight has disappeared, you'll have about half an hour to check the western sky for a broad wedge of faint light extending upwards from the horizon and centered on the ecliptic (i.e., below Mars). That glow is the zodiacal light - sunlight scattered from countless small particles of material that populate the plane of our solar system. Don't confuse it with the brighter Milky Way, which extends upwards from the northwestern evening horizon at this time of year. 

Wednesday, March 3 - Mars near the Pleiades (evening)

(Image credit: Starry Night)

In the western sky on the evenings surrounding Wednesday, March 3, the eastward orbital motion (brown line) of the reddish planet Mars will carry it past the blue-white stars of the Pleiades star cluster, also known as Messier 45, the Seven Sisters, the Hole in the Sky, and Subaru. The planet and the cluster will be only a few finger widths apart for several nights, with Mars positioned to the lower left (or to the celestial south) of the Pleiades. They'll be close enough to easily fit Mars and the Pleiades within the field of view of your binoculars (red circle).

Thursday, March 4 - Minor planet Vesta at opposition (all night)

(Image credit: Starry Night)

On Thursday, March 4, the Earth's orbital motion will carry us between the minor planet (4) Vesta and the sun. Because it will be opposite the sun in the sky, Vesta will be visible all night long, and shine at its brightest for the year (magnitude 5.8) - well within reach of binoculars (red circle) and small telescopes. Look for the asteroid in Leo, approximately one finger's width to the left (or 1 degree to the celestial northeast) of the bright star Chertan. Vesta will travel close to Chertan for a number of nights (red path with labeled dates:time).

Friday, March 5 - Mercury joins Jupiter (pre-dawn)

(Image credit: Starry Night)

On the mornings surrounding Friday, March 5, the speedy planet Mercury will move close to much brighter Jupiter. Look for the duo sitting low over the east-southeastern horizon after they rise together at about 5:15 a.m. local time. At closest approach on Friday morning, Mercury will be located about 20 arc-minutes to the upper left (or celestial north) of Jupiter, allowing both planets to appear together in the eyepiece of a backyard telescope (red circle). The optimal viewing time for observers at mid-northern latitudes will be 5:45 to 6 a.m., before the sky brightens fully. Observers at more southerly locations will see the planets in a darker sky. If your skies aren't clear on Friday, look for Mercury to Jupiter's upper right on Thursday, and to Jupiter's lower left on Saturday.

Friday, March 5 - Third quarter moon (at 8:30 p.m. EST)

(Image credit: Starry Night)

When the moon reaches its third quarter phase at 8:30 p.m. EST on Friday, March 5 (or 1:30 GMT on Saturday, March 6), it will rise in the middle of the night, and then remain visible in the southern sky all morning. At this phase the moon is half-illuminated, on its western side - towards the pre-dawn sun. Third quarter moons are positioned ahead of the Earth in our trip around the Sun. About 3½ hours later, Earth will occupy that same location in space. The ensuing week of moonless evening skies will be ideal for observing deep sky targets.

Saturday, March 6 - Mercury at greatest western elongation (pre-dawn)

(Image credit: Starry Night)

On Saturday, March 6, Mercury will reach its widest angle of 27° west of the sun, and peak visibility for the current morning apparition. Look for the swiftly-moving planet shining very low in the east-southeastern sky, near brighter Jupiter, between about 5:45 and 6 a.m. in your local time zone. In a telescope (inset) Mercury will exhibit a 57%-illuminated, waxing gibbous phase. Mercury's position below the shallowly-dipping morning ecliptic (green line) will make this a poor apparition for mid-Northern latitude observers, but the best showing of 2021 for those located near the Equator, and farther south.

Tuesday, March 9 — Old moon meets Saturn (pre-dawn)

(Image credit: Starry Night)

In the southeastern pre-dawn sky on Tuesday, March 9, the old crescent moon will begin a trip past the bright planets gathered there. When the moon rises it will be positioned less than a fist's diameter to the right (or 8 degrees to the celestial southwest) of magnitude 0.7 Saturn. By the time the sky begins to brighten at about 6 a.m., much brighter Jupiter, and then fainter Mercury, will have risen — forming a line to the lower left (east) of Saturn, and making a lovely photo opportunity when composed with some interesting landscape.

Wednesday, March 10 - Crescent moon near Saturn and Jupiter (pre-dawn)

(Image credit: Starry Night)

The moon's visit with the bright morning planets will continue on Wednesday, March 10, when the slim crescent moon will shift east to sit below and between bright, magnitude -2.0 Jupiter and fainter Saturn. Because the moon will be riding 5 degrees south of the ecliptic, it will rise after Mercury joins the planet party. The scene will make another terrific photo opportunity, especially for observers viewing from more southerly latitudes — where the sun will be farther below the horizon and the moon will be higher.

Thursday, March 11- Old moon below Mercury (pre-dawn)

(Image credit: Starry Night)

Observers viewing from southern latitudes will be able to see the old crescent moon complete its passage of the pre-dawn bright planets on Thursday, March 11. After the moon rises over the east-southeastern horizon, it will shine a palm's width below (or 6 degrees to the celestial southeast) of magnitude 0.0 Mercury — with much brighter Jupiter and slightly fainter Saturn forming a row to Mercury's upper right (west).

Saturday, March 13 - New moon (at 10:21 GMT)

(Image credit: Starry Night)

At 5:21 a.m. EST, or 10:21 GMT, on Saturday, March 13, the moon will officially reach its new moon phase. While new, the moon is travelling between Earth and the sun. Since sunlight can only reach the far side of the moon, and the moon is in the same region of the sky as the sun, the moon becomes completely hidden from view for about a day. After the new moon phase Earth's celestial night-light will return to shine in the western evening sky. 

Sunday, March 14 - Daylight Saving Time begins (at 2 a.m.)

(Image credit: Starry Night)

For jurisdictions that employ Daylight Saving Time (DST), clocks should be set forward by one hour at 2 a.m. local time on Sunday, March 14. For stargazers, the time change, plus the fact that sunset occurs 1 minute later each day near the March equinox, will mean that dark-sky observing cannot commence until much later in the evening — possibly after the bedtime of junior astronomers. The difference from local time to Greenwich Mean Time (GMT), or the astronomers' Universal Time (UT), will be reduced by one hour when DST is in effect. Daylight Saving Time will end on November 7, 2021.

Tuesday, March 16 - Crescent moon near Uranus (evening)

(Image credit: Starry Night)

In the western sky on Tuesday evening, March 16, the young crescent moon will be positioned several finger widths to the lower left (or 3.5 degrees to the celestial southwest) of the planet Uranus — allowing both objects to share the field of view of binoculars (red circle). Normally, visits by the moon make seeing magnitude 5.8 Uranus more difficult — but the 12%-illuminated crescent moon won't be excessively bright. Alternatively, note the brighter stars near the moon that night, such as Menkar in Cetus (to the moon's upper left) and Hamal and Sheratan in Aries (to the moon's upper right) and then use them to locate slow-moving Uranus on a subsequent moonless night.

Friday, March 19 - Moon and Mars (evening)

(Image credit: Starry Night)

In the southwestern sky after dusk on Friday, March 19, look for the reddish, medium-bright dot of Mars shining several finger widths to the lower right (or 3 degrees to the celestial northwest) of the waxing crescent moon. The two objects will appear together in the field of view of your binoculars (red circle). The duo will set together in the west after about 1 a.m. local time.

Saturday, March 20 - Equinox (at 9:37 GMT)

(Image credit: Starry Night)

On Saturday, March 20 at 9:37 GMT (or 5:37 a.m. EDT) the sun will cross the celestial equator traveling north, marking the vernal equinox in the northern hemisphere and the beginning of northern spring. Days and nights will be of equal length on that day, and the sun will rise due east and set due west.

Saturday, March 20 - View the "Lunar X" (at 22:30 GMT)

(Image credit: Starry Night)

Several times a year, for a few hours near its first quarter phase, a feature on the moon called the Lunar X becomes visible in strong binoculars and backyard telescopes. When the rims of the craters Purbach, la Caille, and Blanchinus are illuminated from a particular angle of sunlight, they form a small, but very obvious X-shape. The Lunar X is located near the terminator, about one third of the way up from the southern pole of the Moon (at 2° East, 24° South). The 'X' is predicted to peak in intensity at about 6:30 p.m. EDT on Saturday, March 20. That will be in waning daylight for observers in the eastern Americas - but you can observe the moon in a telescope during daytime, if you take care to avoid the sun. The 'X' will persist until about 8 p.m. EDT. This event should be visible anywhere on Earth where the moon is shining, especially in a dark sky, between 21:00 and 23:59 GMT.

Sunday, March 21- First quarter moon near Messier 35 (at 14:40 GMT)

(Image credit: Starry Night)

When the moon completes the first quarter of its orbit around Earth at 10:40 a.m. EDT (or 14:40 GMT) on Sunday, March 21, the relative positions of the Earth, sun, and moon will cause us to see it half-illuminated - on its eastern side. At first quarter, the moon always rises around noon and sets around midnight, so it is also visible in the afternoon daytime sky. The evenings surrounding first quarter are the best for seeing the lunar terrain when it is dramatically lit by low-angled sunlight. By the time the sky fully darkens in the Americas, the moon's eastward orbital motion (green line) will have carried it about four finger widths to the upper left (or 4 degrees east) of the prominent open star cluster in Gemini known as Messier 35 or the Shoe-Buckle Cluster. That cluster's stars, which are visible in binoculars (red circle), are located to the right of Tejat and Propus, the medium-bright stars that mark Castor's toes.

Monday, March 22 - Mars and Aldebaran (evening)

(Image credit: Starry Night)

In the western sky on the nights surrounding March 20, Mars' eastern motion along the ecliptic will carry it past a "twin", the bright, reddish star Aldebaran in Taurus. Mars will outshine the star only slightly, and their colors will be very similar. During the period of closest approach, around March 18-22, the pair will be separated by 7 degrees, with Mars on the upper right (northerly) side of the star. Mars' better-known twin is the star Antares, the "rival of Mars", in Scorpius.

Wednesday, March 24 - Sinus Iridum's Golden Handle (all night)

march 2021 night sky Sinus Iridum's Golden Handle

(Image credit: Starry Night)

On Wednesday night, March 24, the pole-to-pole terminator that divides the lit and dark hemispheres of the waxing gibbous moon will fall to the left (or lunar west) of Sinus Iridum, the Bay of Rainbows. The circular, 155 mile (249 km) diameter feature is a large impact crater that was partly flooded by the same basalts that filled the much larger Mare Imbrium to its right (lunar east). The "Golden Handle" is produced because slanted sunlight is brightening the eastern (right-hand) side of the prominent, curved Montes Jura mountain range (the old crater rim) that surrounds the bay on the top and left (north and west). The rim extends into Mare Imbrium as a pair of protruding promontories named Heraclides and Laplace at the bottom and top, respectively. You can see the feature with sharp eyes - and easily in binoculars and backyard telescopes. Sinus Iridum is almost craterless, but hosts a set of northeast-oriented dorsae or "wrinkle ridges" that are revealed under magnification at this phase.

Friday, March 26 - Comparing the twins (evening)

march 2021 night sky Comparing the twins

(Image credit: Starry Night)

While the moon is bright and the planets are absent, skywatchers can still enjoy viewing bright stars. The twin stars of Gemini, Castor and Pollux, shine high in the western sky after dusk. A closer look with your unaided eyes will reveal that the twins are quite dissimilar. The left-hand (easterly) star Pollux is nearly twice as bright as sibling Castor to its right (west). Pollux' K0 spectral class gives it a warmer color than white, A1-class Castor. In a backyard telescope Castor is revealed to be a delightful multiple star system, with several fainter companions distributed around a bright, close-together pair. 

Sunday, March 28 - Full Worm Moon (at 18:48 GMT)

march 2021 night sky Full Worm Moon

(Image credit: Starry Night)

While the moon is bright and the planets are absent, skywatchers can still enjoy viewing bright stars. The twin stars of Gemini, Castor and Pollux, shine high in the western sky after dusk. A closer look with your unaided eyes will reveal that the twins are quite dissimilar. The left-hand (easterly) star Pollux is nearly twice as bright as sibling Castor to its right (west). Pollux' K0 spectral class gives it a warmer color than white, A1-class Castor. In a backyard telescope Castor is revealed to be a delightful multiple star system, with several fainter companions distributed around a bright, close-together pair.

Sunday, March 28 - Full Worm Moon (at 18:48 GMT)

march 2021 night sky Full Worm Moon

(Image credit: Starry Night)

The March full moon, known as the Worm Moon, Crow Moon, Sap Moon or Lenten Moon, always shines in or near the stars of Leo. Full moons always rise in the east as the sun sets, and set in the west at sunrise. When fully illuminated, the moon's geology is enhanced, especially the contrast between the ancient cratered highlands and the younger smoother maria. This full moon is occurring 1.5 days before perigee, the point in the moon's orbit when it is closest to Earth, making this the first of four consecutive supermoons in 2021.

Tuesday, March 30 - Zodiacal Light Again (after dusk)

march 2021 night sky Zodiacal Light Again

(Image credit: Starry Night)

At the end of March we receive another opportunity to view the Zodiacal Light - if you live in a location where the sky is free of light pollution. After the evening twilight has disappeared, you'll have about half an hour to check the western sky for a broad wedge of faint light extending upwards from the horizon and centered on the ecliptic (i.e., below Mars). The viewing period will end with the new moon on April 11.

Planets

(Image credit: Starry Night)

The steeply dipping morning ecliptic will keep Mercury just above the eastern horizon during the pre-dawn throughout March — but it will only be observable by mid-northern latitude observers until about mid-month, with the best viewing time landing at 6 a.m. local time. Meanwhile, the Southern Hemisphere will see the best Mercury apparition for 2021! The speedy planet will begin March positioned slightly above and between Jupiter and Saturn, pass within 20 arc-minutes to the north of much brighter Jupiter on March 5, and then reach peak visibility at greatest western elongation, 27 degrees from the sun, on March 6. Viewed in a telescope during the month, Mercury will sport a disk that decreases in apparent diameter from 7.8 to 5.4 arc-seconds, and a phase that waxes from 48% to 85% illuminated. The slim crescent of the old moon will pass well to the south of Mercury on March 10-11.

(Image credit: Starry Night)

Venus will be too close to the sun to see during March. The planet will pass the sun at superior conjunction on March 26, and then Venus will enter the western evening sky for a lengthy stay. 

(Image credit: Starry Night)

Mars' eastward orbital motion along the ecliptic during March will keep it from sliding sunward with the rest of the stars — allowing us to view the planet from dusk until about midnight. In northern Taurus all month long, Mars will pass between the Hyades and Pleiades star clusters on the nights surrounding March 7-8. On those evenings Mars will appear with the Pleiades in binoculars. The bright, waxing crescent moon will hop past Mars on March 18-19. A few nights later, Mars will pass only 7 degrees north of a "twin", Taurus' bright, reddish star Aldebaran. Long past its prominence of October, 2020, Mars continues to steadily fade in brightness and apparent size as Earth pulls away from it. It will shine at magnitude 0.9 on March 1 and fade to magnitude 1.3 on the 31st. Over the same interval, its apparent disk size will decrease from 6.3 to 5.2 arc-seconds.

march 2021 night sky jupiter

(Image credit: Starry Night)

Magnitude -2.0 Jupiter will shine in the east-southeastern pre-dawn sky during March — but the shallow morning ecliptic will keep the planet relatively low, even once it emerges from the morning twilight towards the end of the month. Jupiter and Saturn will both be traveling eastward within the boundaries of Capricornus in March — with fainter Saturn sitting 8-12 degrees to Jupiter's (upper right) west. Fast-moving Mercury will pass 20 arc-minutes to the north of much brighter Jupiter on March 5. The old crescent moon's passage south of the pre-dawn planets from March 9-11 will make several lovely photo opportunities — especially for observers living at tropical latitudes where the moon and planets will shine in a darker sky. Viewed in a telescope during March, Jupiter will exhibit a growing disk that spans about 34 arc-seconds.

(Image credit: Starry Night)

During March, Saturn will shine in a darkened, east-southeastern pre-dawn sky, among the stars of western Capricornus - but the shallow morning ecliptic will keep the ringed planet from climbing very high before sunrise. Magnitude 0.7 Saturn will rise at about 5:40 a.m. local time on March 1 and at 4:45 a.m. at month-end. Much brighter Jupiter will be positioned about 10 degrees to Saturn's lower left (east), and speedy Mercury will move just above and between the gas giants during the first week of the month. The old crescent moon's passage south of the pre-dawn planets from March 9-11 will make several lovely photo opportunities — especially for observers living at tropical latitudes where the moon and planets will shine in a darker sky. When viewed through a telescope, Saturn's mean apparent disk size of 15.6 arc-seconds will increase slightly during March. 

march 2021 night sky uranus

(Image credit: Starry Night)

During March magnitude 5.8 Uranus will be slowly traveling eastward through the stars of southwestern Aries. It will be descending the western sky after dusk — making the blue-green planet an early evening target only. Telescope views of Uranus will show its tiny 3.5 arc-seconds-wide disk. On March 16, the waxing crescent moon will shine 3.5 degrees to the southwest of Uranus. Note Uranus' position about midway between the medium-bright stars Menkar (Alpha Ceti) and Sheratan (Beta Arietis) and search for it with binoculars, or even your unaided eyes, on a subsequent moonless night. 

(Image credit: Starry Night)

Distant blue Neptune will be too close to the sun for observing during March. After it passes the sun at solar conjunction on March 10-11, it will eventually re-appear in the eastern pre-dawn sky.

Skywatching Terms

Gibbous: Used to describe a planet or moon that is more than 50% illuminated.

Asterism: A noteworthy or striking pattern of stars within a larger constellation.

Degrees (measuring the sky): The sky is 360 degrees all the way around, which means roughly 180 degrees from horizon to horizon. It's easy to measure distances between objects: Your fist on an outstretched arm covers about 10 degrees of sky, while a finger covers about one degree.

Visual Magnitude: This is the astronomer's scale for measuring the brightness of objects in the sky. The dimmest object visible in the night sky under perfectly dark conditions is about magnitude 6.5. Brighter stars are magnitude 2 or 1. The brightest objects get negative numbers. Venus can be as bright as magnitude minus 4.9. The full moon is minus 12.7 and the sun is minus 26.8.

Terminator: The boundary on the moon between sunlight and shadow.

Zenith: The point in the sky directly overhead.
 

Night Sky Observing Tips

Adjust to the dark: If you wish to observe faint objects, such as meteors or dim stars, give your eyes at least 15 minutes to adjust to the darkness.

Light Pollution: Even from a big city, one can see the moon, a handful of bright stars and sometimes the brightest planets. But to fully enjoy the heavens — especially a meteor shower, the constellations, or to see the amazing swath across the sky that represents our view toward the center of the Milky Way Galaxy — rural areas are best for night sky viewing. If you're stuck in a city or suburban area, a building can be used to block ambient light (or moonlight) to help reveal fainter objects. If you're in the suburbs, simply turning off outdoor lights can help.

Prepare for skywatching: If you plan to be out for more than a few minutes, and it's not a warm summer evening, dress warmer than you think necessary. An hour of observing a winter meteor shower can chill you to the bone. A blanket or lounge chair will prove much more comfortable than standing or sitting in a chair and craning your neck to see overhead.

Daytime skywatching: When Venus is visible (that is, not in front of or behind the sun) it can often be spotted during the day. But you'll need to know where to look. A sky map is helpful. When the sun has large sunspots, they can be seen without a telescope. However, it's unsafe to look at the sun without protective eyewear. See our video on how to safely observe the sun, or our safe sunwatching infographic.

Further Reading

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