The Messier Catalog

Charles Messier (1730 - 1817) was a comet hunter in Paris in the late 1700’s (and thus in the relatively early years of telescope technology - Galileo first turned a telescope towards the night sky in 1609). The reason he was a comet hunter was that comets had deep astrological and social significance at that time (astrology and astronomy were not segregated as separate endeavors until the late 1800’s - the astronomers prior to that time were also astrologers). Messier kept finding fuzzy objects with his telescope that looked like they might be comets, but when he tracked them he found they didn’t move in the sky (so of course they couldn’t be comets). He compiled a list of them in 1781 to help other comet hunters; only later when telescopes became more powerful did astronomers realize that his “objects to avoid” list was actually a compilation of wonderful star clusters, nebulae, and galaxies.

As a historical note, Charles Messier was not always the person who discovered the objects on his list (nor did he claim to have been). He did personally discover 42 of the 104 original objects on his list; his friend and fellow comet hunter Pierre Méchain discovered 22 of them, and the rest were discovered by other astronomers who then transmitted their “false comet” discoveries to Messier so he could include them on his “objects to avoid” list as a public service to comet-hunters at that time. Messier did actually discover 13 comets, an accomplishment that, ironically and unfortunately, has long since been forgotten.

There are 110 objects on the currently-used Messier List; the last six of them were not on Messier’s original list but were added subsequently by other astronomers (and those six additions are somewhat controversial - if you are the type of person who enjoys engaging in arguments about obscure historical details you would find this controversy to your liking <grin>). As you observe the Messier objects you will discover that Messier’s list has a few idiosyncrasies in it.  He lived through and survived the “Reign of Terror” of the French Revolution, a difficult feat, and he often didn’t have the opportunity to double-check his work so a few of the objects on his list are star asterisms that cause today’s amateur astronomers to wonder why Messier included them on his list at all.  (E.g. M40 is just a faint double star and M73 is just a 4-star asterism.) Nevertheless, as a whole the Messier list is a great place for you to start your deep-sky object observing.