In 1751, went to Paris, where he began to work as a copyist for the astronomer Joseph-Nicolas Delisle (1688-1768). Beginning in 1759, devoted himself to the systematic search for, and study of, comets. His discovery of numerous comets won him election to the Royal Society of London in 1764 and the Académie Royale des Sciences of Paris in 1770. The need to avoid confusing the appearance of a new comet with one of the many cloud-like celestial objects led him to publish a first edition of the Catalogue des nébuleuses et des amas d'étoiles (Paris, 1771). With two later editions in 1780 and 1784, Messier extended the number of objects included in the catalogue to 103. His work, the first of its kind, was very successful. Even today, the objects listed by Messier are identified by their catalogue numbers preceded by the letter M.