Exploring Our Night Sky: January 2021

​January and the start of the year brings us a dazzling array of stars to find our way through, with Betelgeuse and Rigel blazing in Orion (the Hunter), glorious Sirius in Canis Major (the Great Dog) and the bright red Aldebaran in Taurus (the Bull). There is also Capella crowning Auriga (the Charioteer) and Castor and Pollux (the celestial Twins) in Gemini. There is also an opportunity to spot some shooting stars, with the peak of the Quadrantid meteor shower on the night of January 2/3, however it will only be possible to see the brightest of them because of an 84% full moon.

Cut Off - Castle Tioram, Doirlinn, Moidart
On a clear night in January, the Milky Way tracks from south to north over Castle Tioram, which has been cut off by a high, high tide that occurred a few days after a Supermoon.

The Constellations

​This month, the sun sets around 4:15 pm and the stars and the constellations start to become visible from about 6:15 pm onwards. As darkness falls, the most obvious constellation you’ll see is Orion (The Hunter), with its three bright stars in a line, surrounded by a quadrilateral of other stars. You see it rising in the east not long after dark and by 10:00 pm it will be up there in the centre of the southern sky. As it is the brightest constellation in the sky, you’ll be able to see it even when there is a bright moon or some light pollution.

You’ll find Orion by spotting Alnitak, Alnilam and Mintaka, the three stars that line up to make his belt. The Hunter’s shoulders are formed by Bellatrix to the right and the far brighter, blood-red Betelgeuse to the left. The slightly brighter, blue-white Rigel is Orion’s right foot, while the fainter Saiph is his left foot.
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If you follow the line from the three stars of Orion’s belt upwards, you will find Taurus (the Bull). It appears to be charging at Orion, staring him down with a bright red eye, which is the giant red star Aldebaran. Continue to follow this line beyond the Bull’s eye and you will come to The Pleiades, or the Seven Sisters, which is a cluster of young stars that glow blue. In Greek mythology, the Pleiades were the seven daughters of the titan Atlas and the sea-nymph Pleione. Merope, the youngest of the seven daughters, was wooed by Orion.

The Constellation of Orion
Image Credit: By Mouser [CC BY-SA]

You will find Auriga (the Charioteer) directly above Orion. Its brightest star is Capella, which is at the top of a great pentagon of stars that make up the Charioteer’s pointed helmet. At this time of the year, Capella is almost overhead and there is a little group of three fainter stars just to one side of it. There are four other stars in the big pentagon making up the rest of the constellation.
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If you follow the line of Orion’s belt heading left and slightly down, you will find Sirius. It is in Canis Major, the Greater Dog. It is the brightest star in the night sky and appears very low down at our northern latitude. This can cause it to twinkle quite strongly, especially on a clear frosty night.

Canis Major is just one of Orion’s dogs. The other, Canis Minor or the Lesser Dog, can be found directly to his left and its main star is Procyon, the 8th brightest star in the sky. Above Procyon are two stars, Castor and Pollux, which mark the heads of the Twins, Gemini. The bodies of the Twins are the two lines of stars which extend towards Orion.

Another thing you can see in the southern sky is the Winter Circle, a pattern of stars that is not a constellation. It’s made up of a lot of separate stars, in different constellations, so it’s what is called an asterism. It doesn’t form a perfect circle, but instead a hexagon that you can find if you start at Capella and move clockwise to Aldebaran, Rigel, Sirius, Procyon, Pollux, and Castor. In addition to the Winter Circle, Orion’s bright star Betelgeuse forms an equilateral triangle with the stars Sirius and Procyon. This what is called the Winter Triangle.

Southern Night Sky - January 2021
Created using SkyPortal Mobile App

Northern Night Sky - January 2021
Created using SkyPortal Mobile App

​If you go back to Orion’s belt and look carefully about half way down between it and the two stars that mark the Hunter’s left and right feet, you should be able to see a bright patch. This is the Orion Nebula, one of the brightest nebulae, or clouds of gas from which stars are born in the sky. One of many in our Milky Way galaxy, it lies roughly 1,300 light-years from Earth and is some 30 to 40 light-years in diameter. Look at it with binoculars or a telescope and you should see swirls of gas, though the darker and clearer the sky you have, the better. In it, you should also be able to pick out The Trapezium Cluster, which is made up of four bright stars that are only a million or so years old, babies on the scale of star lifetimes.
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Looking North, the thing to bear in mind is that the constellations you see do not change from month to month, it is only their orientation that changes. Look for the seven stars of the Plough, up in the north-east, and the W-shape of Cassiopeia, high up in the north-west at this time of year.  The Plough is known as the Big Dipper in North America. Use its two right-hand stars to point towards the Pole Star, Polaris, which is always in the same position in the sky. Once you’ve found it, you can use it to get your bearings on any night, though all the other northern constellations wheel around it anticlockwise.

Polaris is a second-magnitude star, about the same as the stars in the Plough or Cassiopeia, so don’t expect anything particularly bright. It’s just by chance that this millennium it happens to be very close to the pole of the sky, but there is a slow movement of the sky over the centuries that shifts the position of the stars, and 1000 years ago it wasn’t as close as it is now.

​The Moon

We start the month with a pretty full moon because we had a full moon on 30 December. The last quarter Moon (a half moon) is on 6 January and there is a new Moon (no moon) on 13 January. 

If it’s clear on the morning of 11 January, have look low in the east from about 8:00 am and you will see a very thin crescent moon and Venus rising together. Alternatively, if it’s clear on the evening of 14 January, have look out low in the west about half an hour after sunset and you might spot the very thin crescent Moon above and to the left of Jupiter and Saturn.

​The first quarter moon is on 20 January and will by lying very close to Mars and on the 22 it will be near the Pleiades (Seven Sisters) star cluster.
You’ll see this month’s full moon on 28 January. It is named the Wolf Moon, after the howling of hungry wolves lamenting the scarcity of food in midwinter. Other names include the Moon After Yule, Old Moon, Ice Moon, and Snow Moon.

The Planets

At the start of the month, Mars is brighter than any of the stars in the night sky, with the exception of Sirius, but will fade as it moves away from us through the course of the month. You’ll see it high up in the south to southwest, between Pisces and Aries, before it finally sets at around 1:30 am.
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At the start of the month, Jupiter and Saturn can be seen lying very low on the south-western horizon in the twilight after sunset before finally disappearing from the night sky at about the middle of the month. However, as they disappear, Mercury starts to become visible in this part of the sky for a short period of time. By the end of the month, it will be visible until about 6:00 pm.

This month, Venus continues to be in the morning sky, rising in the south-east at around 6:30 am, but as it’s sinking down into the twilight, it will disappear from view by the end of the month.

​Meteor Showers 

​The Quadrantid meteor shower will peak on the night of January 2 to 3 and would normally put on a good show. This year however, the moon will be 84% full, so you will only be able to see the brightest of its shooting stars. If you do decide to look for them, then the best time is when the meteor shower’s radiant point is at its highest point in the sky. You can find the Quadrantid radiant in the north sky, directly below The Plough and to the left of the bright star, Arcturus and it will be at its highest in the hours before dawn on the morning of January 3. However, as it rises from around 10:00 pm on January 2, you can start watching for shooting stars from then. Also bear in mind that you don’t have to look north as the meteors will appear across all of the sky.