Your guide to the night sky this month
Thursday 1
The planet Mars is closest to Earth today, presenting its largest apparent disc size of 17.2 arcseconds.
This evening’s 54%-lit waxing gibbous Moon sits 3.8° west-southwest of mag. –2.4 Jupiter.
Sunday 4
As midnight approaches tonight and into the morning of 5 December, our Moonwatch target, the 85km-diameter crater Mersenius will be revealed.
Monday 5
The Moon occults Uranus between 16:50 UT and 17:21 UT. Times correct for the centre of the UK and will vary slightly depending upon your location. For more details, see The Big Three.
Thursday 8
The planet Mars is occulted by the full Moon. Disappearance occurs at 04:57 UT, with reappearance at 05:57 UT.
Mars reaches opposition at 05:36 UT. Read more here: The Big Three.
Wednesday 14
The annual Geminid meteor shower reaches peak activity around 13:00 UT. The night of 13/14 December presents the best opportunity for seeing a Geminid meteor, but a bright waning gibbous Moon will interfere.
Thursday 15
The giant moon Ganymede transits the planet Jupiter between 19:02 UT and 22:02 UT.
Sunday 18
The Moon rises just before 02:00 UT, making this a good time to start observing our Deep-Sky Tour. This month we’re looking at objects in and around western Aries.
Tuesday 20
With dark skies as the Moon approaches its new phase, the magnificent constellation of Orion is well-presented for viewing around midnight.
Wednesday 21
Mercury reaches greatest eastern elongation (20.1°), the mag. –0.4 planet visible above the southwest horizon shortly after sunset.
Today is the winter solstice and the longest night of the year.
Thursday 22
With a new Moon tomorrow, this year’s Ursid meteor shower is favourable, peaking around 22:00 UT.
Ganymede transits Jupiter just before it sets. View from 23:05 UT.
Friday 23
Ninth-magnitude comet C/2020 V2 ZTF is just 4° from Polaris this evening.
Saturday 24
Mag. –0.3 Mercury –3.8 Venus and a slender 2%-lit waxing crescent Moon form an attractive triangle, visible shortly after sunset low above the southwest horizon.
Sunday 25
A treat for Christmas: comet C/2022 E3 ZTF is predicted to be viewable with binoculars, reaching mag. +8.0 today. The comet is currently inside the semi-circular constellation of Corona Borealis.
Monday 26
This evening’s 15%-lit waxing crescent Moon lies 4.5° south of mag. +0.9 Saturn.
Thursday 29
This evening’s 48%-lit waxing crescent Moon is 5.4° east of mag. –2.2 Jupiter.
Just after sunset, mag. +0.6 Mercury appears 1.5° from mag. –3.8 Venus, low above the southwest horizon.
Friday 30
This evening’s first quarter Moon will exhibit the popular clair-obscur effects known as the Lunar X and V. Peak visibility is around 21:00 UT.
Saturday 31
As the New Year approaches, bright Mars sits north of the Hyades open cluster, 8° north of mag. +0.8 Aldebaran (Alpha (α) Tauri). It is also located 9° east of the Pleiades.
Family stargazing
Mars is getting bright and really easy to pick out in the night sky as it gets close to opposition on 8 December. Describe it as a bright, orange light in the sky and let your young astronomers try to find it for themselves. Its brilliance is a bit of a giveaway, but the colour is interesting too. Ask how you’d describe the colour. Mars only reaches this brilliance every two-and-a-bit years, due to the way both Earth and Mars orbit the Sun, so explain that this is a special time for the planet. If you have a telescope, take a look and ask what, if anything, can be seen. bbc.co.uk/cbeebies/shows/stargazing
NEED TO KNOW
The terms and symbols used in The Sky Guide
Universal Time (UT) and British Summer Time (BST)
Universal Time (UT) is the standard time used by astronomers around the world. British Summer Time (BST) is one hour ahead of UT
RA (Right ascension) and dec. (declination)
These coordinates are the night sky’s equivalent of longitude and latitude, describing where an object is on the celestial ‘globe’
Naked eye
Allow 20 minutes for your eyes to become dark-adapted
Photo opp
Use a CCD, planetary camera or standard DSLR
Binoculars
10×50 recommended
Small/ medium scope
Reflector/SCT under 6 inches, refractor under 4 inches
Large scope
Reflector/SCT over 6 inches, refractor over 4 inches
GETTING STARTED IN ASTRONOMY
If you’re new to astronomy, you’ll find two essential reads on our website. Visit http://bit.ly/10_easylessons for our 10-step guide to getting started and http://bit.ly/buy_scope for advice on choosing a scope