| Emission nebula | |
|---|---|
| H II region | |
.jpg) VLT Survey Telescope image of the star-forming region Messier 17 | |
| Observation data: J2000 epoch | |
| Right ascension | 18h 20m 26s[1] |
| Declination | −16° 10′ 36″[1] |
| Distance | 5,000–6,000 ly |
| Apparent magnitude (V) | 6.0[1] |
| Apparent dimensions (V) | 11 arcmins |
| Constellation | Sagittarius |
| Physical characteristics | |
| Radius | 11 ly |
| Designations | M17, Swan Nebula,[1] Sharpless 45, RCW 160, Gum 81 |
The Omega 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 by some of the richest starfields of the Milky Way, figuring in the northern two-thirds of Sagittarius. This feature is also known as the Swan Nebula, Checkmark Nebula, Lobster Nebula, and the Horseshoe Nebula,[1][2] and catalogued as Messier 17 or M17 or NGC 6618.
- ^ a b c d e "NGC 6618". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 16 November 2006.
- ^ Cite error: The named reference
psm1876was invoked but never defined (see the help page).