Messier 1, also known as the Crab Nebula, is a supernova remnant from a supernova that happened in 1054, almost 1,000 years ago. In that time, the remnants have expanded to a diameter of 11 light years. It’s expanding at 1,500 km/s. It’s one of the few nebula we can see change in on a human time scale. The nebula is about 6,500 light years away. There is a pulsar at the center of the nebula. It’s the highly compressed core of the original star and has compressed down to a diameter around 18 miles but contains 3-4 solar masses of material. The pulsar spins at 30 times per second.

This image uses all seven common astronomical filters in use by amateurs, luminance, red, green, blue, hydrogen alpha, oxygen III and sulfur II. The first four combine to make a LRGB image which is the actual color of the nebula. Then hydrogen alpha was layered in as red and oxygen III as blue which is approximating natural color. Since sulfur II emission is also red, that is layered in as yellow to make it visually distinct.

This might be my favorite version of the Crab. I’ve imaged it in narrowband twice before but this one is one has more weight to it visually.

This is 42h 30m of LRGBHOS data. For all the technical details, see astrobin.