M110, a small dwarf spheroidal galaxy, is a companion galaxy to M31 - the Andromeda Galaxy. It was imaged with M31 and can be found on my M31 page. M110 is the last entry in Messier's list of objects. Although it was discovered by him in 1773 and then described and sketched by Messier in 1807, he never added it to his catalog. It was later added as the the final object on his list.