The night sky tonight and on any clear night offers an ever-changing display of fascinating objects you can see, from stars and constellations to 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, and a good beginner telescope or binoculars will enhance some experiences and bring some otherwise invisible objects into view. You can also use astronomy accessories 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).
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.
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 email@example.com.
Yearly Night Sky Guides:
Calendar of Observing Highlights
Sunday, December 2 pre-dawn — Venus at Greatest Illuminated Extent
In the early hours of Sunday, December 2, Venus will reach its greatest illuminated extent for the current morning apparition. In a telescope, the planet will show a crescent phase. Despite this, Venus' nearness to Earth of only 0.418 Astronomical Units (38.85 million miles or 62.53 million km) will boost its brightness to a visual magnitude of -4.87. The very bright planet will be visible in the eastern pre-dawn sky after it rises at about 4 a.m. local time.
Monday, December 3 pre-dawn — Old Moon Jumps Venus
In the eastern pre-dawn sky on Monday, December 3, the old crescent moon will occupy a position less than 6 degrees (a palm's width) above Venus. The following morning, the moon's eastward orbital motion (green line) will carry it 8 degrees to Venus' lower left.
Tuesday, December 4 pre-dawn – Old Moon Meets Ceres
In the eastern pre-dawn sky on Tuesday, December 4, the old crescent moon will sit less than 2 degrees (2 fingers widths) to the right of the dwarf planet Ceres. Located in the main asteroid belt, magnitude 8.85 Ceres will be visible in binoculars (orange circle) and small telescopes.
Wednesday, December 5 pre-dawn — Mercury and the Old Moon
When Mercury rises over the east-southeastern horizon at approximately 6 a.m. local time on Wednesday, December 5, it will be sitting less than 5 degrees (about a palm's width) below the very slender crescent moon. When viewed in a telescope, Mercury will exhibit a crescent phase that resembles the moon's. The best time to look for Mercury will occur before 7 a.m. local time.
Thursday, December 6 evening — Mars Very close to Neptune
In the southern sky on the evening of Thursday, December 6, the faster orbital motion of bright, reddish Mars (red path) will carry it close past dim and distant, blue Neptune, allowing owners of small telescopes to easily find Neptune. On Thursday evening, Mars will be situated less than 0.5 degrees west (to the lower right) of Neptune. On Friday evening, Mars will move to land 0.25 degrees east (to the upper left) of Neptune. On both nights, the pair of planets will appear together in the field of view of a telescope at medium to high magnification (orange circle). Minimum separation, with Mars positioned only 2 arc-minutes north of Neptune will occur at 14:05 GMT on December 7 – a sight visible in Western Europe, Asia, and Australia. Note: Your telescope may flip and/or mirror the view.
Friday, December 7 at 2:20 a.m. EST — New Moon
At its new phase, the moon is travelling between Earth and the sun. Since sunlight can only reach the side of the moon facing away from Earth, and the moon is in the same region of the sky as the sun, our natural satellite will be completely hidden from view for about a day.
Saturday, December 8 after sunset – Young Moon Approaches Saturn
For a short period after sunset on Saturday, December 8, the young crescent moon will pass close to Saturn in the southwestern sky. For observers in the Eastern time zone, Saturn and the moon will set while the moon is still 4 degrees to the lower right of Saturn. But the moon's orbital motion (green line) will be carrying it towards the ringed planet. The farther west on Earth you are, the closer the moon will get to Saturn before the duo sets.
Thursday–Friday, Dec. 13–14, midnight to dawn — Geminids Meteor Shower Peak
The Geminids meteor shower, one of the most spectacular of the year, runs from December 4 to 16 annually. In 2018, it will peak before dawn on Thursday, December 14, when up to 120 meteors per hour are possible to see under dark sky conditions. Geminids meteors are often bright, intensely colored, and slower moving than average because they are produced by particles dropped by an asteroid designated 3200 Phaethon. The best time to watch for Geminids will be sunset on Wednesday until dawn on Thursday morning. At about 2 a.m. local time, the sky overhead will be plowing into the densest part of the debris field. The early-setting crescent moon on the peak night will provide a dark sky for meteor-watchers.
Friday, December 14 evening — Moon Meets Mars
In the southwestern evening sky on Friday, December 14, the nearly first quarter moon will be positioned 4 degrees (4 finger widths) to the lower left of reddish Mars. The duo will set in the west at about 11:45 p.m. local time.
Saturday, December 15 at 6:49 a.m. EST — First Quarter Moon
After the moon has completed the first quarter of its orbit around Earth, the relative positions of the Earth, sun, and moon cause us to see it half-illuminated — on its eastern side. A first quarter moon always rises around noon and sets around midnight local time, so it is also visible in the afternoon daytime sky. The evenings around first quarter are the best times to look at the lunar terrain while it is dramatically lit by low-angled sunlight.
Saturday, December 15 pre-dawn — Mercury at Greatest Western Elongation
On Saturday, December 15, Mercury (orbit shown as a red curve) will reach its widest separation west of the Sun for the current apparition. Due to the planet's position above the morning ecliptic (green line), this will be a very good pre-dawn apparition for Northern Hemisphere skywatchers, but a medium-quality one for observers in the Southern Hemisphere.
Sunday, December 16 overnight – Comet Wirtanen Closest to Earth and Near the Pleiades
In the eastern sky during early evening on Sunday, December 16, comet 46P/Wirtanen, which is expected to brighten to almost naked-eye visibility during December, will pass with 4 degrees of the Pleiades cluster in Taurus. On this date, the comet will also be closest to Earth and at maximum predicted brightness. The comet's rapid orbital motion (red path) will produce a noticeable change of position from one hour to the next. During December, Comet wirtanen will move from eastern Cetus, through Taurus and Auriga, and end the month heading towards the star Dubhe in the Big Dipper.
Thursday, December 20 overnight — Moon Crosses the Bull
Starting in mid-evening on Thursday, December 20, the waxing gibbous moon's orbital motion (green line) will carry it directly through the Hyades star cluster, the stars that form the triangular face of Taurus, the bull. The moon will enter the cluster at about 8 p.m. EST. By 4 a.m. EST, the moon will exit the cluster after passing within a degree above the bright foreground star Aldebaran.
Friday, December 21 pre-dawn — Mercury near Jupiter
At about 6 a.m. local time on Friday, December 21, the planets Mercury and Jupiter will rise together from the east-southeastern horizon. Brighter Jupiter will sit only one degree to the lower right of Mercury, allowing both planets to appear within the same field of view of a telescope at low magnification (orange circle). Both objects should remain visible within the morning twilight beyond 7 a.m. local time.
Friday, December 21 at 5:23 p.m. EST – Northern Winter Solstice
On Friday, December 21 at 5:23 p.m. EST, the sun will reach the solstice — its southernmost declination for the year, resulting in the shortest day of the year for the northern hemisphere and the longest day of the year for the southern hemisphere. After the solstice, the amount of daylight will increase daily for the Northern Hemisphere.
Saturday, December 22 at 12:49 p.m. EST — Full Oak Moon
The December full moon, traditionally known as the Oak Moon, Cold Moon, Long Nights Moon, and the Moon before Yule, always shines in or near the stars of Taurus. Since it's opposite the sun on this day of the lunar month, the moon is fully illuminated and rises at sunset and sets at sunrise. Full moons during the winter months in North America reach as high in the sky as the summer noonday sun, and cast similar shadows.
Friday-Saturday, December 21–22 midnight to dawn — Ursids Meteor Shower Peak
The annual Ursids meteor shower, produced by debris dropped by periodic comet 8P/Tuttle, runs from December 17 to 23. It will peak during the early hours of Saturday, December 22, when seeing up to 20 meteors per hour is possible under dark skies. The best time to watch will be from midnight to dawn that morning. Unfortunately, a full moon on the peak night will spoil the show for Ursids meteor watchers in 2018. True Ursids will appear to radiate from a position in the sky above the Little Dipper (Ursa Minor) near Polaris, but the meteors can appear anywhere in the sky.
Monday, December 24 overnight — Moon Buzzes the Beehive
In late evening on Monday, December 24, the orbital motion of the waning gibbous moon (green line) will carry it just below the center of the large open star cluster known as the Beehive (and Messier 44) in Cancer. Both objects will fit within the field of view of a telescope at low magnification (orange circle), although the bright moonlight will obscure the cluster's dimmer stars.
Thursday, December 27 at 10 a.m. EST — Juno Stands Still
On Thursday, December 27, the main belt asteroid Juno will cease a westward retrograde loop (red path) that began in October, and resume prograde motion in front of the distant stars. On that date, the magnitude 8.0 object will be located in the northern part of the constellation Eridanus, the river, and also about 26 degrees to the west of the bright star Rigel in Orion.
Friday, December 28 at 6:06 p.m. EST — Algol at Minimum Brightness
The "Demon Star" Algol in Perseus is among the most accessible variable stars for beginner skywatchers. Its naked-eye brightness dims noticeably for about 10 hours once every 2 days, 20 hours, and 49 minutes because a dim companion star orbiting nearly edge-on to Earth crosses in front of the much brighter main star, dimming its light. On Friday, December 28 at 6:06 p.m. EST, Algol will reach its minimum brightness of magnitude 3.4. At that time, for observers in the Eastern time zone, it will sit more than halfway up the eastern sky. By 11:06 p.m. EST, Algol will be high overhead and will have brightened to its usual magnitude of 2.1.
Saturday, December 29 at 4:34 a.m. EST — Last Quarter Moon
At its last quarter phase, the moon rises around midnight and remains visible in the southern sky all morning. At this phase, the moon is illuminated on its western side, towards the pre-dawn sun. Last 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. After this phase, the waning moon will traverse the last quarter of its orbit around the earth, on the way to new moon.
Mercury will spend December in the eastern pre-dawn sky. Due to Mercury's position north of the morning ecliptic, this will be an excellent appearance for Northern Hemisphere observers, and a poor one for those in the Southern Hemisphere. The best viewing times for mid-northern latitude observers will occur before 7 a.m. local time. On December 15, Mercury will reach a maximum elongation of 21 degrees west of the Sun. Viewed in a telescope during December, the planet will wax from a very slim crescent on December 1 to 89 percent illuminated at month end. Meanwhile, Mercury's apparent disk diameter will shrink by almost half. On the morning of December 21, Mercury will pass within one degree of brighter Jupiter. The two planets will be close enough to appear together in the field of view of a telescope at low magnification.
During December, Venus will shine brightly in the eastern pre-dawn sky, remaining visible until just before sunrise due to its brilliance. The planet will pass from Virgo into Libra at mid-month. As Venus swings farther from the sun throughout December, its disk will wax from 26 percent to 47 percent illuminated and decrease in apparent diameter by a third. Despite only a fraction of its surface reflecting sunlight towards Earth, Venus will peak in brightness at magnitude -4.9 on December 4 because of its relative nearness to Earth. On Monday, December 3, the old crescent moon will occupy a position less than 6 degrees above Venus. The following morning, the moon's eastward orbital motion will carry it to Venus' lower left.
Mars will remain well-positioned for viewing in the southwestern evening sky as a bright reddish, naked-eye object during December because the evening ecliptic has lifted it higher. The planet will be travelling rapidly eastward through Aquarius until December 21, when it will cross into Pisces. On December 6-7, Mars will move closely past Neptune, allowing owners of small telescopes to find Neptune using Mars. For the Americas, on December 6, Mars will be situated less than 0.5 degrees west of Neptune. The following evening, Mars will land 0.25 degrees east of Neptune. On both nights, the pair of planets will appear together in the field of view of a telescope at medium to high magnification. Minimum separation, with Mars positioned only 2 arc-minutes north of Neptune will occur at 14:05 UT on December 7 – a sight visible in Western Europe, Asia, and Australia. As Earth pulls away from the Red Planet, Mars' visual brightness will decrease by a half-magnitude to 0.5 and its apparent disk diameter will decrease from 9.3 to 7.6 arc-seconds. On December 14, the waxing crescent moon will pass 4 degrees to the lower left of Mars.
Jupiter will return to visibility low in the eastern pre-dawn sky after the first week of December, and the magnitude -1.75 planet will escape the morning twilight after mid-month as it climbs away from the sun. Also at mid-month, Jupiter will cross from Scorpius into Ophiuchus. On December 6, the old crescent moon will sit less than 3 degrees to the upper left of Jupiter. On December 21, faster-moving Mercury will pass within a degree of slightly brighter Jupiter. Both objects should remain visible within the morning twilight beyond 7 a.m. local time and be visible as a duo for several mornings.
For the opening days of December, Saturn will remain visible for a short time after sunset as a medium-bright (magnitude 0.55), yellowish object sitting low over the southwestern horizon. For the rest of the month, Saturn will disappear while it migrates towards the sun and will reach solar conjunction on January 2. On December 8 and 9, the young crescent moon will hop over Saturn, landing 4 degrees west on the 8th and 7 degrees east of Saturn on the following evening.
Blue-green Uranus (magnitude 5.8) will be very well positioned for evening observing with binoculars and backyard telescopes during December. The planet will spend the month moving slowly retrograde westward among the stars bordering Aries and Pisces, remaining roughly 1.25 degrees to the northeast of the naked-eye star Omicron (o) Piscium.
During December, deep blue Neptune will be visible in the western sky before midnight. The distant planet will spend the month moving eastward through the stars of Aquarius — shifting slowly away from that constellation's naked-eye star, Hydor (Lambda (λ) Aquarii). That star will sit about 2 degrees to the west of Neptune all month.
Gibbous: Used to describe a planet or moon that is more than 50 percent 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.