Your guide to the night sky this month
Wednesday 1
With the Moon out of the way, this is a great time to enjoy our ‘Deep-sky tour’. This month we’re looking at objects in northern Orion.
Thursday 2
A gorgeous 5%-lit waning crescent Moon graces the morning sky, rising above the southeast horizon shortly before 05:30 UT, as seen from the centre of the UK. Wait just over an hour and Mars will also appear, shining at mag. +1.6.
Friday 3
Rounding off an excellent year of thin Moon spotting opportunities, after Mars rises this morning at around 06:20 UT, a 1%-lit Moon appears about 30 minutes later. Look for the pair low above the southeast horizon.
Saturday 4
If you can grab a view of mag. –4.6 Venus this evening, the planet is currently showing a 25% phase and appears 40 arc seconds across.
Monday 6
The Moon starts its parade of planets this evening. It’s currently an 8%-lit waxing crescent located 5.8˚ from mag. –4.6 Venus, visible low to the southwest shortly after sunset.
Tuesday 7
This evening a 16%-lit waxing crescent Moon sits south of the mid-point between mag. –4.6 Venus and mag. +0.9 Saturn. Venus, Saturn and mag. –2.1 Jupiter currently appear in a line in the evening sky, with Saturn in the middle.
Wednesday 8
This evening, the 22%-lit waxing lunar crescent sits south of the mid-point between Saturn and Jupiter.
Thursday 9
Shortly after sunset the 35%-lit waxing crescent Moon lies 6.7˚ southeast of bright Jupiter.
Saturday 11
A medium to high power view of crater Albategnius around 20:30 UT will show that the shadow cast by its rim appears to reveal the profile of a face. This is the clair-obscur effect known as the Face in Albategnius.
Sunday 12
As the lunar dawn breaks over crater Clavius this evening, the outer rims of two of its inner craterlets catch the Sun’s rays early to form the Eyes of Clavius clair-obscur effect, best seen at 22:20 UT.
Monday 13
The Geminid meteor shower reaches peak activity around 07:00 UT on 14 December, making tonight and tomorrow night ideal times to look for its meteors. A 78%-lit waxing gibbous Moon sets after 03:00 UT on the 14th, leaving three hours of dark sky.
Tuesday 21
At 15:59 UT the centre of the Sun’s disc will reach its lowest position in the sky relative to the stars, an instant in time called the winter solstice in the Northern Hemisphere.
Wednesday 22
The peak of the Ursid meteor shower occurs, but it’s three days after full Moon, meaning the glare washes out the shower.
Ganymede’s shadow crosses Jupiter. The event ends at 18:45 UT.
Friday 24
As the 78%-lit waning gibbous Moon passes its highest point in the morning sky due south, it occults Eta (η) Leonis. From the centre of the UK the star disappears at 04:16 UT, reappearing from behind the Moon’s dark limb at 05:09 UT.
Monday 27
Over a flat southeast horizon, take a look about 07:00 UT. Mag. +1.5 Mars appears 4.5˚ from its rival in the sky, mag. +1.0 Antares (Alpha (α) Scorpii).
Callisto’s shadow transits Jupiter, 12:35 UT to 16:40 UT.
Tuesday 28
Mercury and Venus are close above a flat southwest horizon, 40 minutes after sunset.
You can observe Mercury, Venus, Saturn, Jupiter, Neptune and Uranus this evening.
Friday 31
Mars remains near to its celestial contender, the red supergiant star Antares, literally the ‘rival of Mars’. This morning, set against a brightening dawn sky, the two are joined by an 8%-lit waning crescent Moon.
FAMILY STARGAZING
Six planets are visible in the evening sky towards the month’s end. With the aid of our ‘All-sky chart’ and ‘The Planets’, see how many your young observers can find. Jupiter and Saturn are the easiest; Mercury and Venus need a low, flat southwest horizon. Take care that the Sun has set properly before looking. Uranus and Neptunerequire binoculars. If you manage to see all six, pose the question – which one is missing from the line-up? The answer is Mars, which sits near the star Antares in the morning sky. www.bbc.co.uk/cbeebies/shows/stargazing
NEED TO KNOW
The terms 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
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