The Lake County Astronomical Society

Astronomy Bio...Charles Messier

Jay Bitterman

Charles Messier was born on June 26, 1730, in Badonviller, in the province of Lorraine and died in Paris on April 12, 1817. This French astronomer's work on the discovery of comets led to a compilation of the locations of nebulae and star clusters known as the "Messier Catalogue", which is still of relevance today.

Little is known about him prior to his joining the Paris Observatory as a draftsman and astronomical recorder. Early in Messier's career, his work was acknowledged for its importance and thoroughness, and in 1764 he was elected to the Royal Society in London. Six years later, in 1770, he was also honored by France and made a member of the prestigious Academy of Sciences in Paris.

His interest in comets stemmed from the predicted return of Halley's Comet. Halley (before he died in 1740) calculated that the comet's reappearance would take place around the beginning of 1759. Messier actually sighted its return on January 12, 1759, an experience which inspired him to search for new comets for the rest of his life. (Although he is attributed with being the first person to re-sight the Halley comet on French soil, the German amateur astronomer Palitzch is believed to have been the first to actually see it, on Christmas Day, 1758.)

Messier certainly earned his nickname, the "Comet Ferret", from Louis XV. He spent many hours of painstaking search, for many years, to discover between 15 and 21 new comets. (The actual numbers vary according to the source of information, in any case it's more than fifteen.) During his search of the night sky for comets he was continually hampered by encountering other rather obscure forms which he came to recognize as nebulae and star clusters. Therefore, from 1760 to 1784 Messier set about compiling a list identifying each of these permanent objects. They were numbered and their positions were noted so that other astronomers could easily pinpoint (and thus ignore) these celestial features. The use of the list saved time by reducing the possible confusion with likely new comets.

The project he undertook was an extremely difficult one, considering the equipment he had available. Although there were great improvements with the development (during the first half of the 1700s) of the compound lens, the range and capability of the telescope was still in its infancy. He used a variety of telescopes, the largest being a reflector of about 6-inches; however, the limitations of this instrument eventually prompted him to adopt a refractor of about 31/2-inches. Messier began this work in earnest in 1760, and by 1771 he had completed an initial list of 45 nebulae, giving them an identifying "M" number. Within ten years he had compiled the majority of his catalogue, and by 1784 the list consisted of 103 numbers. Many of his "nebulae" were actually galaxies, but in his time, the nature of galaxies was unknown.

Basically, Messier's original catalogue is still relevant and useful today, with some additions. During the years of 1744 to 1804, his assistant, Pierre Méchain, added six more objects (still during Messier's lifetime). The final object, M110 was added in mid-20^th Century, based on Messier's observing notes. A few purists refuse to accept any objects beyond M103, inasmuch as the latter ones were not recorded by Messier himself. Some doubts inevitably exist as to the reality of some he registered. But there is no doubt as to the presence of such famous astronomical features as the Crab Nebula (Ml), Andromeda (M31), and the Pleiades or Seven Sisters (M45).

(There is a web page devoted to Messier; the URL is: http://seds.lpl.arizona.edu/messier/indexes.html)