Thor's Helmet Bi-Colour Ha & OIII
Thor's Helmet is an interstellar bubble, blown as a fast wind from its bright central star, GSC 5407-3417, sweeps through a surrounding molecular cloud. The central star is a Wolf-Rayet star: an extremely massive giant in a brief, pre-supernova stage of evolution. These stars are very rare, incredibly hot (25,000 - 50,000 K) and expel their outer layers at velocities up to thousands of km/sec.
NGC 2359 is approximately 15,000 light-