Our Night Sky: February 2023

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. Learn how to find your way around them using the Winter Circle, a giant hexagon linking the bright stars Capella, Aldebaran, Rigel, Sirius, Procyon, Pollux, and Castor. Look out for a crescent Moon, Venus and Jupiter sitting very close to each other and spot a Green Comet that last passed by Earth during the Stone Age.​

Sound and Light at Night - Ardnamurchan Lighthouse, Ardnamurchan Point, Ardnamurchan
The now disused foghorn of Ardnamurchan Lighthouse, which sits on the very edge of Ardnamurchan Point, under a starry night sky and the light itself in the background.

The Constellations

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. The most obvious constellation you’ll see as darkness falls 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. If you look south not long after dark, you’ll see it appear 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.

If you follow the line of Orion’s belt heading left and slightly down, you will find Sirius the brightest star in the constellation of Canis Major (the Greater Dog), the larger or Orion’s two hunting dogs which is depicted as chasing Lepus, the Hare – a faint constellation directly below Orion. Sirius is also 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.

The Winter Circle with the Winter Triangle
Image Credit: Elop based on Screenshots from Stellarium
Own work: CC BY-SA 3.0

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.

Southern Night Sky - February
Created using SkyPortal Mobile App

Northern Night Sky - February
Created using SkyPortal Mobile App

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 sky and the W-shape of Cassiopeia, which is 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 because all the other northern constellations rotate around it in anticlockwise direction.
 
Polaris is a second-magnitude star with about the same brightness as the stars in the Plough or Cassiopeia, so don’t expect it to be particularly prominent. It’s just by chance that this millennium it happens to be very close to the pole of the sky because 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 to north 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 Moon

We start the month with a waxing Moon that will become a 100% full Moon at precisely 6:29 pm on 5 February. This means that it will appear full on the nights of 4-5 February, 5-6 February, and 6-7 February. It will rise in the northeast at around 3:15 pm on 4 February, at around 4:30 pm on 5 February and just before 6:00 pm on 6 February.

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 scarcity of 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.
 
The last quarter Moon is on 13 February and the new Moon (no moon) is on 20 February. This means that a few of days before, on 16 and 17 February, you should see the thinnest of crescent Moons sitting low in the southeast in the twilight hours just before sunrise. Similarly, a few of days later, on 22 February, you should be able to pick out the thinnest of crescent Moons sitting low in the southwest sky as darkness falls. Venus will be to its right and Jupiter will be to its left. The following day, on 23 February, a slightly thicker crescent Moon will be higher in the southwestern sky, sitting above and to the left of Jupiter and Venus.
 
We have a first quarter Moon (a half moon) on 27 February and you will find it high in the southern sky, above Orion and close to Mars and Aldebaran. The night before, it will be sitting just below the Pleiades.

The Planets

If you look over to the southwestern horizon as darkness falls, you will spot a brilliantly shining Venus. It has been visible for the past month but is now a lot higher up and therefore easier to spot. This Evening Star is currently brighter than any of the stars and other planets in the night sky, so it will be the first thing you see as darkness falls.

As the days pass, Venus will move towards Jupiter and on 22 February, you will see both planets and a crescent moon all sitting very close together over in the southwest as darkness falls.

Neptune, the faint outermost planet can be found in the same part of the sky and on 15 February will be very close to Venus and visible through a telescope or binoculars.

Jupiter continues to reduce in brightness as the weeks pass but is still shining brighter that any of the stars. You’ll be able to see it quite easily in the southwestern sky before it sets at around 9:00 pm. As always, viewing this gas giant through binoculars or a telescope will allow you to see its famous rings and its biggest moons.

Mars is visible for a good part of the night, before setting at around 3:30 am. You will find it high up in the southern sky, above Orion and in the constellation of Taurus with Aldebaran below it and the Pleiades to its right. The Moon will be very close to it on 27 February.

Uranus is now well below and to the left of the Pleiades, about halfway between Taurus and Aries. It sets at around 1:30 am and you will need a telescope to spot it because it is very faint.

During the first few days of the month, you may be able to see Mercury over in the southeast. It rises at around 6:30 am, so you will have about hour to spot it before the Sun rises.

The Green Comet

​Comet C/2022 E3 (ZTF), or the "Green Comet" was discovered last March by astronomers at the Zwicky Transient Facility at the Palomar Observatory in California. They calculated that it orbits the Sun every 50,000 years meaning that the last time it was visible from Earth was during the Stone Age.
 
It will pass closest to Earth on 1 and 2 February, when it shoots past our planet at a distance of 2.5 light minutes, or a mere 27 million miles.
 
Images taken of comet so far, show it as a fuzzy green ball in the sky with the green glow being due to UV radiation lighting up the gases streaming off the its surface.
 
Comets are unpredictable, so it's difficult to know exactly what to expect on 1 and 2 February. It isn't expected to form a tail that can be seen with the naked eye, but that may change.
 
If you decide to look for it, the morning hours on these two days will be better because the Moon will have set and no moonlight will be present to drown it out. You will find the comet in the northern sky, below and to the right of Polaris, but do keep in mind that it will only be as bright as the dimmest stars and that the light from it will be a fuzzy, diffuse spot. Also, it will help if you find it first by using binoculars and then look without them.
 
If you have difficulty spotting it, try on February 10 because the comet will be sitting very close to Mars and you can use this as a reference point to start with.

Meteor Showers

We in a quiet period for meteor showers and this lasts until 14 April, which is when the Lyrid meteor shower becomes active. It will peak on the night of 22-23 April and the best times to look for meteors will be from late evening on April 21 until dawn on April 22 and late evening on April 22 until dawn on April 23. It should be a good year for spotting them because the new Moon falls on 19 April, meaning that there will be no moonlight to spoil the show.