The Omega Nebula, also known as the Swan Nebula, Checkmark Nebula, Lobster Nebula, and the Horseshoe Nebula[1][2] (catalogued as Messier 17 or M17 and as NGC 6618) is an H II region in the constellationSagittarius. 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.
The Omega Nebula is between 5,000 and 6,000 light-years from Earth and it spans some 15 light-years in diameter. The cloud of interstellar matter of which this nebula is a part is roughly 40 light-years in diameter and has a mass of 30,000 solar masses.[3] The total mass of the Omega Nebula is an estimated 800 solar masses.It is considered one of the brightest and most massive star-forming regions of our galaxy.An open cluster of 35 stars lies embedded in the nebulosity and causes the gases of the nebula to shine due to radiation from these hot, young stars; however the actual number of stars in the nebula is much higher - up to 800, 100 of spectral type earlier than B9, and 9 of spectral type O,plus >1000 stars in formation on its outer regions.
This is an early version in Ha light only.
W.O FLT110 with dedicated TMB field flattener
FeatherTouch 3'' focuser
Starizona MicroTouch autofocuser
W.O ZS80 ED
SBIG ST10XME CFW9
Meade DSI
Filters: Ha 5nm Astrodon
Sky-Watcher EQ6 Pro
Ha:13*10min bin1x1
Total exposure time:2h10min
Astrobin Image of the Day 17 Aug 2014