The
Messier objects are a set of over 100
astronomical objects first listed by
French astronomer Charles Messier in 1771. Messier was a
comet hunter, and was frustrated by objects which resembled but were not comets, so he compiled a
list of them, in collaboration with his assistant
Pierre Méchain, to avoid wasting time on them. The number of objects in the catalog reached 103 during his lifetime but a few more thought to have been observed by Messier have been added by other astronomers over the years.