Calendar of Astronomical Events in December 2023

~7 min
Topics:Skywatching
Sky in December 2023
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All the astronomical events of December 2023 are collected in this guide. Planetary and comet visibility, all the meteor showers, the best stargazing events, and more! Let's get started.

Contents

Astronomical events in December 2023

We provide the event dates in GMT (Greenwich Mean Time). For your location, the exact dates may vary. To find out the time and date of the event for your city, use the Sky Tonight astronomy app.

*The highlighted events are the most spectacular events of the month.

Planets in December 2023

Northern Hemisphere

Mercury (mag -0.5) can be seen very low above the southwestern horizon in the evening in Sagittarius at the beginning of the month. Venus (mag -4.2) is in the southeast in the morning, first in Virgo and then in Libra. Mars is too close to the Sun to be visible this month. Jupiter (mag -2.6) can be seen in the evening in Aries. Saturn (mag 1.0) is visible in the evening in Aquarius. Get binoculars or a telescope to see Uranus (mag 5.6) in Aries and Neptune (mag 7.9) in Pisces in the evening.

Southern Hemisphere

Look for Mercury (mag -0.5) very low above the southwestern horizon for no more than an hour in Sagittarius at the beginning of the month. Venus (mag -4.2) is visible in the east in the morning, first in Virgo, then in Libra. Mars (mag 1.4) is visible in the morning at the very end of the month in Ophiuchus. Jupiter (mag -2.7) is visible in the evening in Aries. Saturn (mag 1.0) rises high above the western horizon in the evening in Aquarius. Use binoculars or a telescope to view fainter Uranus (mag 5.6) in Aries and Neptune (mag 7.9) in Pisces in the evening.

Mercury at greatest eastern elongation

On December 4, Mercury will be at its maximum distance from the Sun in our sky. The time around the greatest elongation is the best time to observe the planet, so don't miss it! Because of Mercury's orbital characteristics, its path in our sky is too close to the Sun, and the planet is often hidden in the Sun's glare. Learn more about Mercury and related events in our dedicated article.

Moon near Venus and Jupiter

One of the easiest events to observe is the conjunction of the Moon and the planets (especially when the planets are bright). Even a casual observer can see this event in the sky with the naked eye.

At the beginning of the month, on December 9, the Moon will pass close to the brightest planet, Venus. While you may miss the exact moment of conjunction, you'll still be able to see the Moon and planet close together as they rise above the horizon. Look for the objects in the morning, before sunrise, in the constellation Virgo.

The second notable conjunction will occur on December 22. On this day, the Moon will meet the second-brightest planet, Jupiter. They will be visible in the sky all night, beginning in the evening. Look for them in the constellation Aries.

Read all the details about the lunar-planetary conjunctions and find the upcoming events in our weekly updated article.

December solstice

On December 22, at 03:27 GMT, the Earth’s Northern Hemisphere will reach its maximum tilt away from the Sun, creating a phenomenon called the winter solstice. People there will experience the shortest day of the year, as the northern half of our planet will have the least amount of daylight. Astronomically speaking, this event marks the beginning of winter in the Northern Hemisphere, which will last until the vernal equinox (March 20, 2024). Our ancestors attached great importance to this day and celebrated it with various festivals — learn more about these peculiar traditions in the article dedicated to the winter solstice.

On the same day, the Southern Hemisphere will tilt closest to the Sun and experience the summer solstice and the longest day of the year. The summer solstice marks the beginning of astronomical summer, which will last in the southern latitudes until the autumnal equinox on March 20, 2024.

By the way, the other planets in the Solar System also have seasons — on Uranus, for example, summer lasts 21 years! Learn more in our article about the summer solstice.

Full Cold Moon

On December 27, at 00:33 GMT, the Full Moon will take place. At that time, the Moon will be in the constellation Gemini. To the naked eye, our natural satellite will appear fully illuminated the day before and after the exact date.

The Full Moon in December is traditionally called the Cold Moon — a name that comes from Native American culture. Native American tribes gave it this nickname to signify the period of cold weather. See the traditional names of other Full Moons in our infographic.

Full Moons 2023
When is the next Full Moon in 2023? When is the Super Blue Moon this year? Check our Full Moon calendar for all dates, times, names, Supermoons, and more for the year.
See Infographic

Meteor showers in December 2023: Geminids, Ursids

Of all the meteor showers that peak in December, the Geminids and Ursids are the most notable.

The Geminids, which peak on December 14, are the best and most reliable of the major annual meteor showers. What's more, in 2023, they will peak around the New Moon, so moonlight won't interfere with observations.

On a dark night around the Geminids' peak, you can see 50 meteors per hour; on the peak night, it's possible to see 150 meteors per hour. In the Northern Hemisphere, the meteors will be visible from the local evening hours. In the Southern Hemisphere, they will be visible around local midnight.

Ursids peak around the solstice on December 23. During the peak, they provide 5 to 10 meteors per hour. This year, the 87% illuminated Moon may interfere with observations. So wait until our natural satellite sets, which will give you about three moonless hours before sunrise. This shower is best viewed from northern latitudes.

Comets in December 2023

Here are some of December's best comets — visible through binoculars or a telescope. To find their exact location in the sky, use the Sky Tonight astronomy app.

The short-period comet 62P/Tsuchinshan will reach its perihelion on December 25, 2023. During this time, it will be well positioned in the sky for observation. The comet is expected to reach a magnitude of about 9, which means it will be bright enough to be observed with binoculars. Unfortunately, it will fade quickly after that. The comet will be best seen from the Northern Hemisphere.

The short-period comet C/2021 S3 (PANSTARRS) is expected to brighten to magnitude 7 in early 2024, around perihelion on February 14; in December 2023 it will have a magnitude of 10-11. The comet favors the Southern Hemisphere and stays extremely low above the horizon in the Northern Hemisphere.

The short-period comet 12P/Pons-Brooks is now gradually brightening on its way to perihelion on April 21, 2024. In December, it will have a magnitude of about 9, but keep an eye out for sudden outbursts of brightness! In the last two months, it has brightened twice suddenly, on October 5 and November 14. In the Northern Hemisphere, the comet will gradually get lower. In the Southern Hemisphere, it is not yet visible.

How to navigate the night sky?

For non-professional astronomers, the night sky can be tricky and confusing. Which of these bright dots is Venus? Where to look to find a particular comet in the sky? The easiest and fastest way is to use an astronomy app like Sky Tonight. It's free to use, works without an internet connection, which is useful when camping, and includes a handy astronomical calendar.

Open the app, point your phone at the sky, and Sky Tonight will tell you the names of constellations, stars, and more. If you want to get really good at knowing what's in the night sky, there are videos that can teach you how to use the app.

Also, you can test your practical skills in night sky observation with the quiz! Are you just a newbie stargazer or an almighty Astro Maestro? Find out!

How Good Are You at Stargazing?
Can you tell a star from a planet and a satellite from a plane? Do you know basic asterisms? Test your stargazing skills and knowledge with this quiz!
Take the quiz!

Bottom line: space events in December 2023

In December 2023, skywatchers will be in for a treat with some interesting events happening in the sky. There's a fantastic meteor shower, the Geminids, and you can also see bright Venus and Jupiter near the Moon. Keep an eye out for the magnificent Full Cold Moon, too! You may even see several comets if you have binoculars or a telescope. Also, December brings a change in seasons with the solstice. To find all the beautiful objects in the sky easily, check out the Sky Tonight astronomy app. Enjoy looking at the stars!

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