Messier 17 object data
The Omega Nebula, also known as the Swan Nebula, Checkmark Nebula, and the Horseshoe Nebula (catalogued as Messier 17) is an H II region in the constellation Sagittarius. It was discovered by Philippe Loys de Chéseaux in 1745. Charles Messier catalogued it in 1764. It is located in the rich starfields of the Sagittarius area of the Milky Way.