Thor's Helmet

Object Type: Emission Nebula
Scope: Orion 10" Newtonian; Exposure 75 minutes.

Thor's Helmet (NGC 2359) is an emission nebula in Canis Major, about 12,000 light-years away and some 30 light-years across. Its helmet-and-wings shape is blown by the powerful wind of the central Wolf-Rayet star WR 7, an extremely hot, massive star in a brief, violent stage shortly before it is expected to explode as a supernova. The bubble's complex filaments and curved bow-shock arise from that wind sweeping up surrounding gas and colliding with a nearby molecular cloud.