A portrait of Messier, at the center, surrounded by pictures of objects of his catalog taken by the Hubble Telescope
The Messier objects are a set of 110 astronomical objects catalogued by the French astronomer Charles Messier.
This catalog is one of the most famous lists of astronomical objects, and many Messier objects are still referenced by their Messier numbers.
The first edition of 1774 covered 45 objects (M1 to M45). The total list published by Messier in 1781 contained 103 objects, but the list was expanded through successive additions by other astronomers, motivated by notes in Messier's and Mechain's texts indicating that at least one of them knew of the additional objects.
The Messier catalogue comprises nearly all the most spectacular examples of the five types of deep-sky object - diffuse nebulae, planetary nebulae, open clusters, globular clusters, and galaxies - visible from European latitudes. Furthermore, almost all of the Messier objects are among the closest to Earth in their respective classes, which makes them heavily studied with professional class instruments that today can resolve very small and visually spectacular details in them.
A portrait of Messier, at the center, surrounded by pictures of objects of his catalog taken by the Hubble Telescope