It's February and the winter constellations of Orion, Taurus, Auriga and Gemini continue to fill our night sky as they make their annual journey westward. During the first part of the night, you can see them in the south and, using Orion’s belt as a guide, you can easily find your way around them. Another good signpost or guide is the Winter Circle asterism, a giant hexagon linking the bright stars Capella, Aldebaran, Rigel, Sirius, Procyon, Pollux, and Castor.
This month, the sun sets around 5:20 pm and the stars and the constellations start to become visible from about 7:20 pm onwards. In addition, the night sky for this month is very similar to last month’s with Orion (the Hunter) Taurus (the Bull) and Auriga (the Charioteer) filling much of it. As darkness falls, the most obvious constellation you’ll see is Orion, which can easily be found by spotting the line of three bright stars (Alnitak, Alnilam and Mintaka) that make up Orion’s Belt. You’ll see it appear not long after dark if you look in the sky to the south along with the quadrilateral of other stars that surround it to make up Orion’s torso and legs. His 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.
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.
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.
Orion’s other dog, 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.
If you go back to Orion’s belt and look carefully about halfway 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.
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, which is 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.
As Capella is pretty much overhead you will also see it when you are looking north. It is the sixth-brightest star in the night sky, and the third-brightest in the northern celestial hemisphere after Arcturus and Vega. You’ll find Arcturus over in the North-East. It is the brightest star in the constellation of Boötes (the Herdsman), the fourth-brightest in the night sky, and the brightest in the northern celestial hemisphere. You’ll find Vega low down on the northern horizon. It is the brightest star on the constellation of Lyra (the Lyre), the fifth-brightest in the night sky, and the second-brightest in the northern celestial hemisphere.
The first quarter Moon (a half moon) is on 8 February and will high up in the southern sky as darkness falls, while this month’s full Moon is on 16 February, becoming 100% full at 4:56 pm. This means that it will appear full on the nights of 15-16 February, 16-17 February, and 17-18 February. It will rise in the north-east just before 4:00 pm on the 15 February, at about 5:00 pm on the 16 February and at about 6:30 pm on 17 February.
On the night of 20-21 February, the Moon will spend the night traversing the sky close to Spica, the brightest star in the zodiacal constellation Virgo.
The last quarter Moon is on 23 February and on 26 February, you will see it rising in the south-east at about 6:30 am, with Mars and Venus to the left of it.
This month’s full Moon is called the Snow Moon after the snowy weather typically found in North America in February. Some North American tribes named it the Hunger Moon due to the scarce food sources during mid-winter, while other names are Storm Moon and Chaste Moon, but the last name is more common for the March Full Moon.
Jupiter hangs low in the south-west for around an hour after sunset before it drops below that horizon at about 6:30 pm. This gas giant is the fifth planet from the Sun and the largest our Solar System and if you look at it through binoculars or a telescope, you should be able to see its four bright moons.
Once Jupiter has set, the only two planets on view for most of the night are Neptune and Uranus, the two faint outermost worlds in our solar system. If you look in the two hours after sunset, you may be able to spot Neptune low down in the south-west before it sets at about 7:30 pm. Meanwhile, you will find Uranus between the constellations of Taurus and Aries, quite high up in the south-west sky.
If you want to see more planets, you will need to look in the pre-dawn sky. Venus rises in the south-east from about 5:30 am and at a magnitude of -4.6, it will far outshine any star. Mars rises in the south-east about an hour later and you will find it pretty much below Venus, but it will be considerably fainter at a magnitude of +1.3.
We are now in a quiet period for meteor showers, until the Lyrid meteor becomes active on 16 April. It will peak on the night of 21-22 April and the best time to look for them will be between sunset and when the moon rises at about 3:30 am.