Messier 110 (also known as M110 and NGC 205) is a dwarf elliptical galaxy that is a satellite of the Andromeda Galaxy. M110 contains some dust and hints of recent star formation, which is unusual for dwarf elliptical galaxies in general.
Although Charles Messier never included the galaxy in his famous list, it was depicted by him, together with M32, on a drawing of the Andromeda galaxy; a label on the drawing indicates that Messier first observed NGC 205 on August 10, 1773. The galaxy was independently discovered by Caroline Herschel on August 27, 1783; her brother William Herschel described her discovery in 1785. The suggestion to assign the galaxy a Messier number was made by Kenneth Glyn Jones in 1967.
In 1999, Johnson and Modjaz discovered a nova in M110.