The Omega Nebula, also known as the Swan Nebula, Checkmark Nebula, and the Horseshoe Nebula 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.

Magnitude: 6

Distance: 5,000-6,000 ly

Constellation: Sagittarius

Coordinates: RA 18h 20m 26s | Dec -16° 10′ 36″

Apparent dimensions (V): 11 arcmins

Did you know: The Omega Nebula is between 5,000 and 6,000 light-years from Earth and it spans some 15 light-years in diameter.