The Messier Catalogue

The Messier Catalogue (pronounced Meh-see-ay) is a catalogue of cosmic objects published in 1781 by the French Astronomer Charles Messier. These deep-space objects are non-stellar (i.e. not stars) and are well beyond our solar system.

Over more than two decades he compiled a list of 103 cosmic objects (in order to not confuse them with the comets in our solar system that we was actually searching for) some of which were discovered by Messier himself. The Messier Catalogue contains almost all of the spectacular deep-space objects visible from Earth — especially those in the

He catalogued the best examples of the various types of deep-sky objects — supernova remnants, open star clusters, globular star clusters, planetary nebulae, diffuse nebulae, and galaxies — missing a few of objects in the southern sky as he could only see to about 35.7° south of the celestial equator from where he worked in Paris (-35.7° celestial latitude). [2]

Today the list of Messier Objects in the Messier Catalogue has been expanded to 110.

Building the Messier Catalogue

In the decades following the invention of the telescope around 1609, during the time of Galileo Galilei, the magnification provided by the telescope opened the eyes of astronomers to a new world. It was discovered that there are vastly more stars in space than can be seen with the naked eye.

As telescopes became more common, and more powerful — a consequence of their increasingly widespread use combined with human ingenuity — the universe only expanded. As the increasing power of telescopes accentuated the optical power of our eyes, fainter and fainter cosmic objects were witnessed for the very first time by humans.

Beginning around 1759 Charles Messier (a French astronomer) began listing things objects, a task that he began by necessity as his search for comets was being interrupted by these faint objects that were not stars, and were well beyond our solar system.

This list eventually became the Messier Catalogue published in three editions over about 13 years. The first edition of the Messier Catalogue contained 45 objects (M1-M45) and was published in 1774. By 1780 that list had increased to 70 objects (M1-M70), with the final version being published in Connaissance des Temps pour l’Année 1784 [Knowledge of the Times for the Year 1784] reaching a total of 103 objects (M1-M103). [2]

Over two decades he identified 103 of these cosmic objects that are non-stellar (not stars) and beyond our solar system. compiling them into a list that he published in 1784 in what we now call the Messier Catalogue — which he continued to refine over the subsequent years. [1]

Today the Messier Catalogue contains 110 cosmic objects known as Messier Objects — mainly Star Clusters, Nebulae, and distant Galaxies — which from the perspective of our Solar System are located in essentially every direction around us in space, distributed throughout the sky except for the deep southern sky.

Resources

1. A Guide To Skywatching. David H. Levy. 1994, 2002.
2. “Messier Object”. Wikipedia. <https://en.wikipedia.org/wiki/Messier_object>. Accessed 14 Aug 2024.