Thor's Helmet Nebula
Thor’s Helmet is an emission nebula located in the constellation Canis Major. The nebula is approximately 12,000 light years away and 30 light years in size. The central star of the nebula is a hot star thought to be in a pre-supernova stage of evolution which gives the large molecular cloud its complex shape and structure. 118 sub frames at 5 minutes each comprise this image for just a touch under 10 hours total exposure time.