| M31, The Andromeda Galaxy |
| Probably the most distant object you will ever see with your naked eye |
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Following close behind the Summer Triangle, the Great Square of Pegasus is easy to find in the Autumn sky. It is quite a large object with each side of the square about 15 degrees long. (Spread your hand and hold it at arms length; 15 degrees is approximately the distance between the tips of your index and little fingers.) The 'top left' star in the square is called Alpheratz or alpha andromedae, which tells us it's really part of the constellation Andromeda. It is a useful starting point for finding the Andromeda Galaxy.
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Andromeda and Pegasus are closely linked. Alpheratz, the star at the 'top left corner' of the Square of Pegasus is really part of Andromeda. It's a good starting point for finding the great Andromeda Galaxy. |
Possibly the most distant object you will ever see with your naked eye, the Andromeda Galaxy is the nearest spiral galaxy to the Milky Way |
Start at Alpheratz and count two bright stars to the left, then two fainter stars up. M31, the Andromeda Galaxy is just above the second faint star and to the right. If you can't see it, try looking at a nearby star. This technique is called 'averted vision' and brings into play the more light-sensitive part of your retina. On a clear, dark night you should be able to see it when looking directly at it. Through binoculars it is easy to see and looks like a sausage-shaped cloud.
Its outer spiral arms only show up in long exposure photographs when its true size becomes apparent. It is about three degrees long, i.e. six times the diameter of the Sun and full Moon.
Both pictures were generated using Chris Marriott's SkyMap Pro software.
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