The Ring Nebula is one of the most incredible sights in the sky and its discovery has been historically attributed to French astronomer Antoine Darquier de Pellepoix. But recent archival work, conducted by Professor Donald Olson from Texas State University and Italian astro-historian Giovanni Maria Caglieris, revealed that he was not the first.
The discoverer was actually Charles Messier, a contemporary of Darquier, known for the groundbreaking catalog of galaxies, star clusters, and nebulae that became known as the 110 Messier objects. The confusion on the identity of the discoverer is actually due to Messier’s own catalog and the language that he uses. This fascinating story is reported in the latest issue of Sky & Telescope.
The Ring Nebula is known in the catalogs as M57 and was discovered by Messier on January 31, 1779, while he was looking at Bode’s comet. Messier was an avid comet hunter (he discovered 13 comets in his life) and the catalog was designed to help other astronomers to not confuse fuzzy extended distant objects with comets.
"In comparing the comet to β Lyrae on this morning, I observed in the telescope a small patch of light… this patch of light was round and was located between γ & β Lyrae," the January 31 entry from Messier’s notes says.
And in the catalog, he reports: "Darquier in Toulouse discovered this nebula, while observing the same comet."
This has been for 238 years the end of the story. But in reality, the confusion is due to the language that Messier used. In the 1700s, the French term for “discover”, decouvrir, was a common synonym of observing and Messier used the same term when he talked about his observations of Bode’s comet.
The researchers looked at a letter Darquier sent to Messier himself, where he talked about how he started his observation of Bode’s comet during the second week of February and how he saw the same Nebula. The dates unmistakably confirm Messier as the discoverer.
The Ring Nebula is known as a planetary nebula. A red giant star at its center has been expelling material, forming shells of ionized gas. The Ring Nebula is located 2,300 light-years away and can be resolved with a small telescope.