The Messier Objects

Messier objects are stellar objects, classified by astronomer Charles Messier in the 18th century, ranging from distant galaxies to star clusters to stellar nebula. The catalog was a major milestone in the history of astronomy, as it was the first comprehensive list of deep sky objects. Ironically, Charles Messier wasn't all that interested in the objects in his list. He made the catalog in order to avoid mistaking those objects for comets, which were his true passion.

Messier objects are identified by Messier Numbers. The first object in Messier's catalog, the Crab Nebula, is labeled M1. The last object, M110, is a satellite galaxy located in the constellation Andromeda. There is no systematic ordering in the Messier Catalog. Messier entered objects into the list as he found them. Sometimes he made mistakes and once he entered the same stellar object twice. The catalog has undergone some slight revisions since Messier's time, correcting the mistakes in the original.

One of the great pursuits for amateur astronomers is to do a Messier Marathon, trying to view all of the objects in Messier's catalog in one night. Unfortunately, if you want to see all of them, you have to start looking right after sunset and continue until just before sunrise - hence the term, "marathon." March is the only month in the year in which an astronomer can run the complete marathon.

You can learn more about the Messier Marathon at Wikipedia and Stargazer's Online Guide.

M01: The Crab Nebula

M1, known as the Crab Nebula, is one of the most famous supernova remnants in the night sky. The supernova was first noted on July 4, 1054 by Chinese astronomers. At its height, the supernova was about four times brighter than Venus and could be seen during the day for a period of more than three weeks.

M13: Hercules Globular Cluster

M13 is one of the most prominent and best known globular clusters of the Northern sky. It was discovered in 1714 by the noted English astronomer, Edmund Halley. Located in the Hercules constellation, M13 is visible to the naked eye on clear nights in dark sky locations.

M16: The Eagle Nebula

M16, better known as the Eagle Nebula, is located in the distant constellation, Serpens. The source of light for M16 is the high-energy radiation of the massive young stars being formed in its core. By studying M16, astronomers hope to learn more about the early years of our own Sun.

M20: The Trifid Nebula

M20 is a red emission nebula with a young star cluster located at its center. The astronomer John Herschel was the first to use the term, "Trifid" to describe this nebula's appearance. Charles Messier referred to M20 only as a "cluster of stars".

M27: The Dumbbell Nebula

M27, or the Dumbbell Nebula, was the first planetary nebula ever discovered. It is probably similar in structure to the Ring Nebula (M57) though its appearance is very different due to the angle by which it's viewed.