Take a break from the festive hurly-burly, as Stuart Atkinson brings you a cosmic countdown to the big day with 25 celestial treats to find in the night sky this December
As the countdown to Christmas begins, we bring you glad tidings: if you have ‘buy advent calendar!’ on your shopping list, you can scribble it out, because this year we’ve produced a special astronomical advent calendar just for sky-watchers. There are no little cardboard doors to prise open and no strange-tasting chocolate snowmen to eat. Our calendar is the winter night sky and we’re giving you 25 different, glorious sights to find in the run-up to Christmas.
So cross your fingers for good weather, because after you’ve dumped your shopping bags, and grabbed a cuppa and a mince pie, you can wrap up warm and head outside to enjoy a winter wonderland of bright planets, beautiful constellations and sparkling star clusters.
Many of our targets are visible with the naked eye, while some require binoculars or a small telescope. Stay clear of light pollution if you can and allow 30 minutes for your eyes to adapt to the dark. Use a red torch to find your way and turn your smartphone screen red if you want to consult an astronomy app, as this will help preserve your night vision.
Each target is visible throughout December, so if one night is cloudy, just pick the next clear night and find a few of them. Our final target, however, is something of a Christmas present.
On Christmas Day afternoon, head outside in your Christmas jumper and catch a lovely gathering of the Moon and two planets in the twilight. Merry Christmas everyone. Let’s get started!
1 Mars
Recommended equipment: Binoculars, small telescope
The December sky belongs to Mars! Although known as the Red Planet, Mars is more of an orange colour in the sky, and this month it’s a bright, marmalade ‘star’ blazing in Taurus, close to the Hyades and Pleiades star clusters. During early December, it reaches mag. –1.9, making it brighter than anything else around it, and the planet reaches opposition on the 8th. Even a small telescope will reveal the southern polar ice cap and dark markings on its surface.
2 Uranus
Recommended equipment: Large telescope
Shining at mag. +5.7, Uranus is technically visible to the naked eye, but unless you know the sky very well and can tell exactly which of the many faint lights in Aries is the ice giant planet, you’ll need binoculars to pick it out. If you spot a green-hued ‘star’ 15.5° to the west of the Pleiades star cluster after dark, you’ve found Uranus!
3 Jupiter
Recommended equipment: Binoculars, small telescope
Half an hour after sunset on December evenings, look to the southeast and you’ll see a bright blue-white ‘star’ shining above the skyline, obvious to the naked eye at mag. –2.4. This is Jupiter, the largest planet in our Solar System. With binoculars you’ll be able to see up to four of its family of 80+ moons, and a telescope will show horizontal bands of toffee- and coffee-hued cloud on its slightly flattened creamy disc.
4 Saturn
Recommended equipment: Small telescope
Having found Jupiter shining in the southeast, look to its south and slightly lower in the sky to see another planet: Saturn. At mag. –0.8, the ringed giant is fainter than Jupiter and more of a yellow-white hue. You’ll need a telescope to see its famous rings, but binoculars will reveal its largest moon, planet-sized Titan, shining close by.
5 The Plough (aka The Big Dipper)
Recommended equipment: Naked eye
One of the most famous night-sky sights of all, The Plough isn’t actually a constellation but an asterism, a small pattern of stars obvious to the naked eye. The Plough is part of the constellation Ursa Major. As darkness falls on December evenings, it looks a lot like a question mark of stars low in the north.
6 Mizar/Alcor
Recommended equipment: Binoculars
This double star can be found in the centre of the Plough’s handle. You may be able to split the pair with your naked eye, but if not then a pair of binoculars or a small telescope will give you very crisp views. Mizar, the brighter of the two, shines at second magnitude, while fainter Alcor has a brightness of mag. +4.
7 Polaris
Recommended equipment: Naked eye
Many think that Polaris, aka The Pole Star, is the brightest star in the sky, but at mag. +1.97, it is only the 48th brightest. However, it is perhaps the most important star in the northern sky because it is almost directly above Earth’s north polar axis, and as our planet spins all the stars appear to wheel around it while it seems to remain stationary.
8 Double Cluster
Recommended equipment: Small telescope
Located roughly halfway between the ‘W’ of Cassiopeia and the inverted ‘Y’ of Perseus, this pair of star clusters, so close together they are almost touching, is a favourite of many amateur astronomers. Visible as a smudge to the naked eye, binoculars and small telescopes reveal two clusters of pinprick stars, looking like piles of salt spilled on a black tabletop.
9 Cassiopeia
Recommended equipment: Naked eye, binoculars
This small constellation is an unmistakable highlight of the northern sky. If you face south after dark and tilt your head right back, almost directly overhead you’ll see a ‘W’ of silvery white stars all of roughly the same brightness. Because Cassiopeia is embedded in the Milky Way, if you sweep your binoculars around it you will see countless thousands of fainter stars.
10 Caroline’s Rose
Recommended equipment: Small telescope
Caroline’s Rose is an open cluster in Cassiopeia named in honour of astronomer Caroline Herschel, sister of William. Around 8,000 lightyears away, its flowery name comes from its loops and curls of orange and blue stars that form the shape of rose petals when viewed through a telescope.
11 M31
Recommended equipment: Naked eye, small telescope
To the naked eye M31, the Andromeda Galaxy, is an elongated smudge below Cassiopeia, but through binoculars or a small telescope you will see it is a beautiful, lens-shaped patch of misty light much larger than the full Moon, with a noticeably brighter centre. A giant spiral galaxy, bigger than our own Milky Way, it is 2.2 million lightyears away – the most distant object visible to the naked eye.
12 M33
Recommended equipment: Small telescope
Although not as large in the sky as its near neighbour M31, and a lot fainter too (mag. +5.8 vs mag. +3), M33, the Triangulum Galaxy, can just about be seen with the naked eye on nights of good seeing under skies free of light pollution. Through binoculars and telescopes this face-on spiral galaxy looks like a small, round smear. Larger telescopes and long-exposure photos reveal its beautifully curved spiral arms, mottled with star clouds.
13 M15
Recommended equipment: Small telescope
Globular clusters are huge balls of many thousands of stars and 6th-magnitude M15 is among the brightest and most observed globulars in the sky. It is 175 lightyears across but 34,000 lightyears away, so it looks like an out-of-focus star to the naked eye and a round smudge in binoculars. With a telescope it is a much more impressive, tightly packed cluster of silvery-grey stars.
14 Vega
Recommended equipment: Naked eye
One of the three strikingly bright stars that make up the famous Summer Triangle asterism, Vega is still clearly visible in the sky over the festive period. At mag. +0.03, Vega is the fifth-brightest star in the whole sky. You’ll find it shining low in the west as the sky grows dark, a beautiful blue-white spark of light. By midnight it will be almost scraping the horizon, but then it will start to climb higher again, never quite setting.
15 M57
Recommended equipment: Small telescope
Just under 7° away from Vega, planetary nebula M57 is famously known as the Ring Nebula because of its smoky, ring-like appearance through a telescope. Planetary nebulae are the results of dying stars puffing off their outer layers, and while there are larger examples elsewhere in the sky, M57 is greatly loved for its beautiful colours. It looks like an out-of-focus green star through binoculars.
16 Orion
Recommended equipment: Binoculars
Considered by many to be the most handsome and dramatic constellation in the sky, Orion, The Hunter’s starry hourglass dominates the view throughout December. By 8pm all its brightly-coloured stars are clear of the horizon, shining like jewels low in the east. Ruddy mag. +0.6 Betelgeuse and fierce bluewhite mag. +0.3 Rigel shine diagonally opposite each other, on either side of the famous Belt. Read our Explainer for more advice on observing this wonderful constellation.
17 Orion’s Belt
Recommended equipment: Small telescope
This diagonal line of three icy stars pulled tightly around Orion’s waist is one of the most famous asterisms in the sky and a striking sight as they rise above the horizon on frosty December nights. The three are all around second magnitude (as bright as Polaris). Through binoculars you’ll see many fainter stars shining around them.
18 Orion Nebula
Recommended equipment: Naked eye
There are many bright nebulae in the sky, but the Orion Nebula, M42, is in a class of its own. Glowing in the centre of Orion’s Sword, which hangs down from the left side of the Belt, the nebula is a ghostly patch to the naked eye. Binoculars show it as a feathered, grey smudge, while telescopes reveal it to be a beautiful cloud of grey-green light, with dark notches and streamers silhouetted across it.
19 Sirius
Recommended equipment: Naked eye
The brightest star in the sky, Sirius blazes to the lower left of Orion. Because it never rises very high in the sky from mid-latitudes like the UK, it is always seen through the turbulent air above the horizon and so appears to flash and scintillate dramatically through the long winter nights, glinting like a finely-cut diamond. Seen through a telescope it is literally a dazzling sight.
20 M41
Recommended equipment: Binoculars
Lying only 4° south of brilliant Sirius, this mag. +4.5 open star cluster is often overlooked, but it is as lovely a sight as many better-known clusters. Around 100 stars can be seen with the naked eye and it is very pretty through binoculars.
21 M44
Recommended equipment: Binoculars, small telescope
Also known as the Beehive Cluster, M44 is not high in the sky until after 10pm on December evenings, but it is worth waiting for. Very obvious to the naked eye as a large smudge of stars in the centre of Cancer, at only 577 lightyears away M44 is one of the nearest star clusters to us. It contains around 1,000 stars, hundreds of which can be seen through binoculars or a small telescope.
22 The Hyades
Recommended equipment: Binoculars, small telescope
Representing the sharp horns of Taurus, the Bull, this V-shaped star cluster is obvious to the naked eye to the upper right of Orion. Lying on its side like a mathematical ‘greater than’ symbol, the Hyades contains several hundred stars. Its brightest star, the orange-hued Aldebaran, is not actually part of the cluster; it just happens to lie in the same direction as seen from Earth.
23 The Pleiades
Recommended equipment: Binoculars, small telescope
Many observers believe the Pleiades, M45, is the most beautiful star cluster in the sky. To the unaided eye it is an eye-catching knot of seven blue-white stars – hence its popular nickname ‘The Seven Sisters’. Binoculars reveal dozens more stars dotted around the seven brightest, and through a telescope the Pleiades is a spectacular spray of stars: so many that they spill out over the edge of even a low-power eyepiece’s field of view.
24 Aldebaran
Recommended equipment: Naked eye
Rising in the east early on Christmas Eve night and throughout December is the red giant star Aldebaran. It’s found in Taurus and is known as the ‘red eye of the bull’. The star appears to be in the Hyades cluster but is actually much closer to Earth. Find it by extending the line of Orion’s three Belt stars up and to the right. Aldebaran is also part of the Winter Hexagon asterism: it’s a great jumping-off point to star-hop to some wonderful widefield targets.
25 Mercury, Venus and a shining crescent Moon
Recommended equipment: Naked eye, binoculars
On Christmas Day afternoon, just as the Sun sets, catch the brief but lovely sight of a gathering not of three wise men, but three shining bodies just above the southwest horizon: the silver sliver of a crescent Moon and the planets Mercury and Venus. They will be visible to the naked eye, but much more obvious through binoculars, and in the same field of view. Venus will be the brighter of the planets, with fainter Mercury just under 4° away. You should also be able to see the unlit part of the Moon’s face glowing a soft lavender hue. This is ‘Earthshine’, sunlight that has been reflected off Earth and onto the Moon’s surface, a stunning sight through binoculars and small telescopes.
Stuart Atkinson is a lifelong amateur astronomer and author of 11 books on astronomy