I was quite surprised when not just two but three gas shells were captured after 6 hours of hydrogen alpha exposures in this image of planetary nebula NGC2438! I decided to do a long Ha exposure after I noticed hints of a second outer shell in a red POSS2 image. The magnitude 10 planetary nebula is in the foreground of M46, a beautiful open star cluster in the constellation Puppis.
An earlier image by Don Goldman that captured the second gas shell can be found here: http://dg-imaging.astrodon.com/gallery/display.cfm?imgID=206
07h 42' -14d 46'
Date Imaged :
March 10, 2011
Astrodon HaRGB 360:42:30:46 minutes
Stardust Observatory, Baguio