The Ring Nebula, a popular deep sky object for observers, was discovered by 18th-century astronomer Charles Messier, not by his colleague Antoine Darquier, who has been credited with seeing it first.
Researchers at Texas State University found notes written by both astronomers confirming that Messier first saw the nebula on January 31, 1779, when looking for Bode’s Comet while Darquier’s first spotting of it occurred in the second week of February that year.
Messier is known for publishing the Messier Catalogue, a list of 110 deep sky objects. Used by astronomers today to observe these objects, the catalog’s original purpose was to assist comet hunters by giving them a list of objects to avoid in their searches.
In the publication, the Ring Nebula is listed as M57 and described upon discovery as a small, round patch of light.
While the entry includes specific measurements regarding the nebula’s location, indicating he was the first person to see it, it also states, “Darquier in Toulouse discovered this nebula, while observing the same comet.”
Because numerous historical documents have been uncovered and made available online over the last 25 years, previously unknown documents have come to light, among them Darquier’s own records.
These records include a letter from Darquier to Messier with detailed notes indicating he first observed the Ring Nebula during the second week of February 1779.
Scholars led by Texas State University astronomer Donald Olson believe the confusion may have originated due to a slight difference in the meaning of the word “discover” during the 18th century.
At that time, discovering an object simply meant observing it rather than being the first to find or see it. Messier used the word “discover” to describe his observation of Bode’s Comet fully knowing it was first found by astronomer Johann Bode.
Notably, Darquier also created a catalog of celestial objects, in which the Ring Nebula is the sole nebula listed.
The research team’s findings will be published in the June 2017 issue of Sky and Telescope.