Messier 31 or the Andromeda galaxy as it is better known is located in, yes you guessed it, the constellation Andromeda. This beautiful spiral galaxy is the nearest to our own Milky Way galaxy and lies at a distance of around 2.2 million light years. The galaxy shines at magnitude 3.4 and can just about be seen with the naked eye as a very dim patch of light. Indeed, the Persian astronomer , Al Sufi, referred to it as "Little Cloud" as early as 905 A.D.
Very similar to our own galaxy, M31 spans 150,000 light years and has a mass of around 200-300 billion suns. M31 is a perfect example of a "Sb" type spiral galaxy. It's galactic plane is oriented about 13 degrees to our line of sight and therefore we see it nearly edge-on. The galaxy has 2 satellite galaxies which have also been designated with the Messier numbers M32 and M110.
Unfortunately, M31 is rather disappointing when viewed with a small telescope. The problem is that it is always described as a very bright showpiece object and to be honest, you really need a large telescope to see it in all it's glory. Having said that, it is still worth a good look because the core does show up very bright. Incredibly though, with a 14 inch telescope some of the galaxies numbered globular clusters can be seen, with the brightest being G76.
The galaxy is a superb object for any camera, although it is huge and so you will need a telescope with a large field of view to capture it all. As you can see by my photographs, my telescope does not! The Andromeda galaxy is best observed and photographed in the Autumn and Winter months in the northern hemisphere.
To finish, I must tell of a strange conspiracy story of M31, which goes like this. What we perceive as M31 is actually our own galaxy! Some unknown entities have constructed a gigantic mirror in space, so when we look at M31 we are actually looking at our own galaxy reflected back to us. Amazingly, the conspiracy theorists do not actually tell us who has the technology to do this or why. Odd, that.