Charles Messier (26 June 1730 – 12 April 1817) was a French astronomer most notable for publishing an astronomical catalogue consisting of deep sky objects such as nebulae and star clusters that came to be known as the 110 "Messier objects". The purpose of the catalogue was to help astronomical observers, in particular comet hunters such as himself, distinguish between permanent and transient visually diffuse objects in the sky.
The first version of Messier's catalogue contained 45 objects and was published in 1774 in the journal of the French Academy of Sciences in Paris. The final version of the catalogue was published in 1781, in Connoissance des Temps for 1784.[2] The final list of Messier objects had grown to 103.
On several occasions between 1921 and 1966, astronomers and historians discovered evidence of another seven deep-sky objects that were observed either by Messier or his friend and assistant, Pierre Méchain, shortly after the final version was published. These seven objects, M104 through M110, are accepted by astronomers as "official" Messier objects.
The objects' Messier designations, from M1 to M110, still are in use by professional and amateur astronomers today.
The catalogue is not organized scientifically by object type, or even by location as the later New General Catalogue would be. On the other hand, 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. Because these objects could be observed visually with the relatively small-aperture refracting telescope (approximately 100 mm, or four inches) used by Messier to study the sky, they are among the brightest and therefore most attractive deep sky objects observable from earth, and are among the most popular targets for visual study and photography available to modern amateur astronomers using larger aperture equipment. Furthermore, almost all of the Messier objects are among the closest to our planet 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.
This image gallery consists of the Messier Catalogue objects and nothing else.