Atlas Image mosaic of Messier 31, the Andromeda Galaxy. This is one of the most famous Messier objects in the sky, and certainly one of the most famous galaxies. Two additional galaxies, the much smaller spheroidal objects, are also seen in the 2MASS image mosaic: Messier 32, to the south, and NGC 205, to the northwest, which are satellites of the giant spiral M31. All three are members of the Local Group of galaxies, which includes the Milky Way, the Large Magellanic Cloud, the Small Magellanic Cloud, Messier 33, and other smaller dwarf galaxies. It is through Edwin Hubble's work in the 1920's on M31, which is at a distance of 765 kpc (2,493,900 light years), that we first became aware that other galaxies exist beyond the Milky Way. The Local Group is a gravitationally-bound aggregate of galaxies, which is a subunit of the much larger Local Supercluster of groups and galaxy clusters, including the Virgo Cluster. M31 is so bright and extended on the sky that, at a dark site, it can be seen with the naked eye.