Thor's Helmet is composed of cosmic dust and gas, which is revealed to have a blue-green appearance through astrophotography. It is an emission nebula (ionized gas that emits its own light) about 12,000 light years away in the constellation Canis Major (The Great Dog). It's a helmet-shaped cosmic cloud with wing-like appendages and measures about 30 light years from one side to the other. At a magnitude of 11.45 (human eye visibility is 6.5 max) this cannot be seen with the naked eye and is 8 arc-minutes across, so not very large.

This image was captured with 4.5 hours’ worth of 3 minute exposures taken the end of February.

Thanks for looking!