This is planetary nebula PK205+14.1, but its common name “The Medusa Nebula” rolls off the tongue a little better.
About 1500 light-years away within the constellation Gemini, you’re seeing the gas blown off by a small star that ran out of fuel, and blew up into a red giant – later to end its life as a white dwarf. That’s exactly what our sun is expected to do in a few billion years. You will not want to be around when that happens.
The star that made this mess is the faint one near the center of the bright crescent. Its radiation makes ionized oxygen gas glow blue/green, and ionized hydrogen gas glow red in this image.
11 hours of exposure time over the past two nights.