Andromeda galaxy. Enhanced optical image of the Andromeda galaxy (M31, NGC 224). This is the closest major galaxy to our own, lying around 2.2 million light years away in the constellation Andromeda. It is the largest galaxy in our local group, around 180,000 light years across. It has two satellite galaxies associated with it: M32 (bright star-like point below M31's nucleus) and NGC 205 (fainter, above and right of M31's nucleus). This image was produced by a CCD (charge-coupled device) camera, which stores images electronically rather than on film.