Pierre François André Méchain was a French astronomer and surveyor who, with Charles Messier, was a major contributor to the early study of deep-sky objects and comets.
Portrait of Méchain, c. 1882
Charles Messier was a French astronomer. He published an astronomical catalogue consisting of 110 nebulae and star clusters, which came to be known as the Messier objects, referred to with the letter M and their number between 1 and 110. Messier's purpose for the catalogue was to help astronomical observers distinguish between permanent and transient visually diffuse objects in the sky.
Charles Messier, c. 1770
Messier's grave in Père Lachaise
The Orion Nebula as drawn by Messier, and which he gave the designation M 42 in his catalogue
Commemorative plaque in Messier's hometown of Badonviller