NGC7293 Helix Nebula; Aquarius
250mm f/4 Mak Newt astrograph
ST-10XME HaRGB 275:40:40:40 min.; unbinned
July 31 - Aug 2, 2006; Inkom, ID
Comments: The Helix Nebula is the largest planetary nebula. This is maily due to the fact that it is relatively close, being approximately 522 light years away. It measures 1.8 light years in diameter.The central star is extremely hot and radiates strong ultraviolet radiation. This radiation in turn ionizes the oxygen atoms in the central void which then give off a blue-green glow. The periphery of the nebula glows red-orange from the concentrated hydrogen and nitrogen atoms in this part of the nebula. Wide field version.