Rensselaer Astrophysical Society

I'm afraid I can't tell you how to pronounce "Messier", but I can tell you what astronomers mean when they refer to Messier objects. Charles Messier (1730 - 1817) was a French astronomer who made a career of discovering comets. During his careful surveys of the sky, he came across many objects that were not comets. These objects were known as nebulae. Very little was known about these nebulae, and oddly enough, very few people cared. They were seen as having very little importance to the field of astronomy. Nevertheless, Messier began to catalogue these objects, recording their positions and descriptions.

His list was first published in the Memories de l'Academie in 1774, and contained 45 objects. In later years, supplements were added onto the list. The final total is 110 objects, although there is room for debate as to how many there actually are. A few of the 110 objects were never published by Messier, but were attributed to him upon reviewing his notes after his death. A couple of objects were recorded by him, but astronomers are unable to identify what it was that he claimed to be looking at, and a couple of objects appear to be duplicates.

So what are these objects, anyway? About the only thing they have in common is that they aren't comets. the Messier catalogue contains galaxies, remnants of super nova, globular clusters, open clusters, emission nebulae, and planetary nebulae. They were all found through telescopes built in the 18th century, so they are all easily visible in today's amateur telescopes. This makes Messier's catalogue a list of treasures for the amateur observer. Objects are designated by M, followed by a number. Below is listed some of the more well-known objects:

Viewing all of the Messier objects is a great way to explore the night sky, because of the variety of objects and their relativly bright magnitude (under clear, dark skies you should be able to view all with a 6" telescope, although some are easier then others). You can download a checklist to keep track of how many you have observed.