IntroductionCharles Messier (1730 - 1812) was a French astronomer who, between 1774 and 1781, published his Catalogue des nébuleuses et des amas d'étoiles, a list that eventually grew to contain 110 galaxies, nebulae and star clusters. Most objects in the catalogue are still known by their 'Messier number', although a few are more usually referred to by their common names (e.g. the Orion Nebula, M42, the Pleiades, M45, and the Whirlpool galaxy, M51).The first part of Messier's catalogue contained 45 objects, although three of the last four entries - the great nebula in Orion (M42) and two bright star clusters, Praesepe (M44) and the Pleiades (M45) - were well known naked eye objects and were probably only included so that Messier's catalogue contained more entries than Lacaille's 1755 catalogue of 42 objects in the southern sky. By 1781 the catalogue had grown to contain to include 103 objects, although one object, M102, is probably a duplicate of M101 (as claimed by Mechain, its dicoverer) or maybe an obervation of the galaxy NGC5866. The modern catalogue contains an extra seven objects, based on evidence that Messier knew of them. The most recent, M110, was added in 1966 by Kenneth Jones. M110 is a satellite galaxy of M31, and was visible in a drawing of M31 made by Messier. To me, the most interesting entries in the catalogue are a collection of 16 objects in Virgo and Coma Berenices that Messier observed as he followed the comet of 1779. The words 'nébuleuse sans étoile, dans la Vierge' became so frequent in his catalogue that Messier noted that 'The constellation of Virgo, and especially the northern wing, is the constellation that contains the most nebulae'. Messier was making the first observation of a cluster of galaxies, the Virgo cluster. 220 years later, Galaxy clusters were the subject of my PhD thesis. Because the Messier objects are bright enough to have been seen in the late 18th century, they make ideal targets for amateur astronomers. I'm slowly working my way through the list: 34 down, 76 to go... Messier Images
Go back to the main page. |