Exploring the stars during NAW 2020

As well as the planets, there are some great sights to see in the skies during National Astronomy Week. In addition to learning the main constellations, you can see the Andromeda Galaxy, count the Seven Sisters and see the glittering Double Cluster, among other things. If you'd rather watch a video of the actual sky, take a look at the stars for National Astronomy Week.

You may have an app on your phone which will help you explore the sky. However, apps don’t always help you learn the sky, but just tell you what you’re looking at. Follow our sky guide to get to know the stars for yourself.

Here’s a map of the sky during NAW, based on the Stellarium software program. Because it is a map of the sky you need to hold it over your head, and as a result east and west are reversed compared with a map of the ground. If you prefer you can print out a black-on-white version. The map is for 6 pm on the 17th, but if you use it later in the evening Jupiter and Saturn will have moved over to the west or will have set, while features towards the east such as Mars will have risen a bit.

The sky as seen from the UK on 17 November 2020 at 6 pm

We have joined a few star patterns with lines to help you, but as this is a map of the whole sky condensed down into a small area, the actual patterns are bigger than they look on the map.

Start with Mars – you can’t miss it because it really is the brightest thing around until the Moon appears towards the end of the week. Above it and to the left is a large square – well, almost a square – of four stars, about the same brightness as the stars of the Plough which is over to the north. This is the Square of Pegasus. 

Once you’ve identified that, look for another pattern, a larger triangle, made of three bright stars. Deneb is almost overhead, while Vega is a bit to the west of it. Altair is lower down, and has fainter stars on either side. This group is called the Summer Triangle, but of course it’s visible in autumn as well and remains well into the winter. 

Deneb is at the top of a large cross, which we have joined by lines. This is the constellation of Cygnus, the Swan, and Deneb is its tail, but it’s also thought of as the Northern Cross. It is much bigger than the better-known Southern Cross, which we can’t see from the UK. 

Shown faintly on the map is the Milky Way. You need to be in a dark country area to be able to see this, but on a really dark night with no Moon it’s an amazing sight. However, most people these days have never seen it, so if you aren’t locked down, try and get out into the country and take a look. 

The Northern Cross points along the sky to five stars in the shape of a W, which is the constellation of Cassiopeia. A bit farther on are the stars of Perseus. Between Perseus and the Square of Pegasus notice two fairly bright stars, which are in the constellation of Andromeda. More about these in a while. 

The last constellation we’ve marked is one of the best known of all, over in the North. People in the UK call it the Plough, while in North America they call it the Big Dipper. The French call it la Casserole, or saucepan, which is as good a name as any. Actually, its proper name is Ursa Major, the Great Bear. The two stars opposite the handle of the Plough or dipper or saucepan point to another star of similar brightness. This is Polaris, the Pole Star. It is close to the point in the sky which the rest of the sky turns around, so it is virtually stationary in the sky. This means that once you’ve found it from your observing location, it will always be in the same spot, due north. In six months’ time, the Plough will be overhead and Cassiopeia will be close to the horizon, and the other constellations will all have changed, but Polaris will be in the same spot. 

Now for some of the showpieces of the sky. 

The Pleiades

First, look below Perseus and you will see a tiny group of stars which is called the Pleiades (pronounced ‘Ply-a-deez’). The individual stars are not bright but together they are unmistakable. Try to count them. Here’s a clue – they are also known as the Seven Sisters. 

Actually, there are many more than seven, and if you have binoculars do take a look at them as you’ll be able to see dozens. This is a young cluster of stars, recently formed – by which we mean within the past few million years.

How to find the Pleiades starting from Perseus
How the Pleiades appear through large binoculars in a dark sky

The Double Cluster

Between Perseus and Cassiopeia is a much fainter but richer cluster, or rather a pair of clusters, called the Double Cluster. You’ll need a dark sky to see these properly, and while they are visible with the naked eye in a good country sky as a fuzzy patch, they really come into their own with binoculars or a small telescope. There are literally thousands of stars here.

The Double Cluster lies between Perseus and Cassiopeia
Closeup of the Double Cluster

The Andromeda Galaxy

This is the most distant object you can usually see with the naked eye. It’s another galaxy, like our own Milky Way, 2½ million light years away. That means that its light took 2½ million years to get here before it struck your retina. It can be seen with the naked eye from a good country sky and with binoculars even from city centres on really clear nights. 

To find it, start with the Square of Pegasus and count two stars to the left and two stars up, as shown here. Or you can draw a diagonal through the Square and get to roughly the right spot.

To find the Andromeda Galaxy, count two stars along from the top left of the Square of Pegasus, then two stars up. It lies near the top star

There’s a trick to seeing it if it doesn’t show up straight away, one that astronomers use all the time to see faint objects. This is called averted vision, and it means looking slightly away from the object itself rather than directly at it. You don’t see as much detail, but it shows up well enough that you can see that it is an oval of light.

How the Andromeda Galaxy appears in large binoculars in a dark sky

Actually, all you see in most cases is the brightest central part rather than the outer arms of the galaxy, but in truly dark skies it appears quite large. Being a galaxy, it contains not just thousands of stars like the Double Cluster, which is within our own Milky Way galaxy, but maybe a hundred billion or more. It is roughly a twin of our own galaxy, and is a spiral galaxy seen inclined to our line of sight.

Long-exposure photo of the Andromeda Galaxy. Photo: Ian King

Last Updated: 2020-12-30 22:48:56