The Omega Nebula, also known as the Swan Nebula (catalogued as Messier 17 or M17 and as NGC 6618) is an w:H II region in the w:constellation Sagittarius. It was discovered by w:Philippe Loys de Chéseaux in 1745. w:Charles Messier catalogued it in 1764. It is located in the rich w:starfields of the Sagittarius area of the w:Milky Way.
Omega Nebula from w:Hubble Space Telescope
|Observation data: w:J2000 epoch|
|Right ascension||18h 20m 26s|
|Declination||−16° 10′ 36″|
|Apparent magnitude (V)||+6.0|
|Apparent dimensions (V)||11 arcmins|
|Absolute magnitude (V)||-|
|Other designations||M17, NGC 6618,|
Swan Nebula, Sharpless 45, RCW 160, Gum 81
The Omega Nebula is between 5,000 and 6,000 w:light-years from w:Earth and it spans some 15 light-years in diameter. The cloud of interstellar matter of which this w:nebula is a part is roughly 40 light-years in diameter. The total w:mass of the Omega Nebula is an estimated 800 w:solar masses.