The Andromeda Galaxy is one of the brightest Messier objects and it is possible to make out the galaxy on a moonless night as a faint fuzzy smudge. It is, in fact, the most distant object visible to the naked eye. The galaxy is home to around a trillion (10¹²) stars, some three times more than our own galaxy, the Milky Way, making it the largest galaxy in our local group. It is thought that the Milky Way is very much like the Andromeda Galaxy, with our star, The Sun, residing in one of the outer spiral arms. When you look up at the Milky Way on a dark night, you are looking along the plane of the galaxy. If you look south towards the horizon, the brighter patches of the Milky Way are areas closer to the glowing centre of our galaxy. Unfortunately, the centre itself is below the southern horizon for me in Marlborough.

Commonly referred to as The Great Andromeda Nebula in some old texts, William Huggins was the first to notice that the Andromeda Galaxy differed in appearance from the gaseous nebula it was originally thought to be. A supernova in 1885 helped identify the object as a collection of stars. The galaxy has been widely studied ever since and there is debate as to whether it has a bar or not.

It is the closest major galaxy to Earth and is also blueshifted, approaching the Milky Way at a velocity of around 110 km/s. The galaxy is predicted to collide with our galaxy in 3.8 billion years, forming one much larger elliptical galaxy.

There are two further Messier objects in this image; galaxies M32, left, and M110, right. The majority of the stars in the image are part of the Milky Way, with the Andromeda Galaxy an island beyond the veil of stars of our own galaxy.