NGC 7217
M17 - Swan Nebula
Messier 17 is one of the brightest nebulae in the sky. It is called by many different names including the Swan Nebula, the Omega Nebula, the Horseshoe Nebula, and "the checkmark". The nebula contains also about 30-40 stars which form a fairly new cluster. These young stars light the nebula and since hydrogen gas glows red when excited by the stars photons, the nebula appears red. The whitish region is not due to overexposure but is believed to be a mixture of reflection and emission from the young stars. Stats for M17 are RA: 18h 20m 45.0s, Dec: -16° 10' 00", Mag: 6.9, Size: 11.0'x6.0', Class: E.
Optics: Celestron C11 F/11 (3100mm Focal Length) Date: August 8, 2007
Camera: SBIG ST10XME with Adaptive Optics Location: Columbus, Texas
Exposure: LRGB = 150:50:70:80 minutes Imager: Kent E. Biggs