The Crab Nebula is M1 and the Andromeda Galaxy is M31. Over a hundred deep-sky objects with "M" numbers are listed in the Messier Catalogue. Charles Messier, 18th-century comet hunter, is known today less for his comets and more for his catalog of things that aren't comets.
Charles Messier - Comet Ferret Charles Messier, born June 26, 1730, was not only a keen comet hunter, but so successful at finding comets that the King of France nicknamed him "the comet ferret". While looking for comets, Messier encountered nebulae, which were also fuzzy objects in the sky. This inspired him to begin his catalogue of nebulae so that they wouldn't trip up other astronomers.
