Messier objects

Messier object

Messier objects, taken and compiled by an amateur astronomer
Survey type	astronomical catalog
Target	nebula, planetary nebula, open cluster, globular cluster, galaxy
Named after	Charles Messier
Published	1771
Band	visual perception
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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 lists he published reached 103, but a few more thought to have been observed by Messier have been added by other astronomers over the years.

A similar list had been published in 1654 by Giovanni Hodierna, but attracted attention only recently and was probably not known to Messier.

The first edition covered 45 objects numbered M1 to M45. The total list published by Messier finally 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 first such addition came from Nicolas Camille Flammarion in 1921, who added Messier 104 after finding a note Messier made in a copy of the 1781 edition of the catalogue. M105 to M107 were added by Helen Sawyer Hogg in 1947, M108 and M109 by Owen Gingerich in 1960, and M110 by Kenneth Glyn Jones in 1967.M102 was observed by Méchain, who communicated his notes to Messier. Méchain later concluded that this object was simply a re-observation of M101, though some sources suggest that the object Méchain observed was the galaxy NGC 5866 and identify that as M102.