Perfect Astronomy

What to See in December's Night Sky (2021)

Published December 1, 2021 by Tim Trott in News

Monthly guide for what to see in December 2021 including comets, planets, meteor showers and more!

Decembers Moon Phases

In December, winter sets in and the Full Moon is called the Cold Moon. It is also called Long Nights Moon, and the Moon before Yule.

Full Moon and New Moon for December 2021

New Moon
New Moon
Sat 4th Dec
First Quarter
First Quarter
Sat 11th Dec
Full Moon
Full Moon
Sun 19th Dec
Last Quarter
Last Quarter
Mon 27th Dec

Notable Events in December

Predicted to be the brightest comet of the year, comet Leonard (C/2021 A1) should be visible with binoculars, and it may become a naked-eye comet!

Comet Leonard, Looking East before SunriseComet Leonard, Looking East before Sunrise

December Planets

Six planets of the Solar System are going to be visible in throughout December 2021, with a beautiful planetary parade occurring over the Christmas holidays.

Jupiter, Saturn and Venus are visible throughout December, but the best time to see the 6-planet parade will be from 28 December to 3 January, 30 minutes after sunset.

Looking SW after sunset, Jupiter, Saturn and Venus are visibleLooking SW after sunset, Jupiter, Saturn and Venus are visible

Mercury is also visible beneath Venus, however may be too low on the horizon for most viewers in the UK. Mercury and Venus need a low, flat southwest horizon and will be best seen through binoculars. Take care that the Sun has set properly before looking, though, as observing the Sun through binoculars will seriously damage your eyes.

Neptune is a binocular planet too which is easy to locate. Simply follow the line from Saturn to Jupiter and extend it the same distance to find Neptune.

Mars returns in December as an early morning planet, visible from around 6.30am low on the south eastern horizon. Viewers in northern latitudes may have difficulty due to the low position, however this improves January into February.

December Meteor Showers

The annual Geminid Meteor Shower takes place in December, with the peak on the 13th. It’s one of the favourite observing events of the year with many bright meteors expected to be visible.

Geminid Meteor ShowerGeminid Meteor Shower

The Geminid meteor shower reaches peak activity around 14th December, making 13th and 14th December ideal times to look for meteors. The Geminids provide good activity prior to midnight as the constellation of Gemini is well placed from 10pm onward. Around the peak of the 2021 Geminid meteor shower, the Moon is in an advanced waxing phase. Although it will be 78% illuminated in a waxing gibbous phase on the evening of 13/14th December, it sets around 03:00 UT on 14 December. Given the long dark December nights, this means there will still be around three hours of darkness left to enjoy what the shower has to deliver.

December Deep Space Objects

The Orion Nebula (M42 and M43) are prime targets in the winter months hanging in the South Eastern sky. They are easy to locate as they form the sword hanging from Orion's Belt.

Taurus contains two glorious winter deep sky objects - the Hyades and Pleiades star clusters. Both can bee seen with the naked eye and are wonderful sights in binoculars, and small telescopes will further reveal the glittering array of bright, blue stars that make up the Pleiades.

A short hop into neighbouring Auriga will bring you to the three exquisite open clusters - M36, M37 and M38 all of which can be spotted with binoculars and lie in the region between Beta Tauri and Delta Aurigae.

With dark skies, you should be able to spot the double cluster Perseus with the naked eye. It's another great target for small telescopes and consists of the clusters NGC 869 and NGC 884.

The Crab Nebula (M1) is almost directly overhead during the early evening hours. You do need a dark, clear sky, for to see the Crab nebula as it has a tendency to get lost in light pollution. It may be just barely visible as a dim patch of light in good binoculars, whilst telescopes greater than 3" should be able resolve more detail.


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