The famous Crab Nebula is the gaseous remnant of a supernova that was seen (and recorded) by Chinese and Arab astronomers in 1054. More than seven hundred years later, French astronomer Charles Messier was looking for the return of Halley's Comet when he came across this nebula. He thought at first that it was a comet. When he realized that it was not, he started compiling a catalog of nebulae that looked like comets so that he would not be confused again. In his catalog, he called this nebula "Messier 1" or "M1." Ironically, M1 was again confused with Halley's Comet when the comet returns in 1835.
For astrophotographers, the tangled tendrils of reddish gas make this a unique target. High-resolution (i.e., a large telescope) helps to capture the detail in these filaments, but even smaller scopes show the distinctive structures.
Capturing M1
M1 is bright enough to take some magnification. The image above was taken with an 8" telescope at f/4, but it probably would have been better to try f/8.
Nevertheless, because there is no central bright core to M1 (unlike most galaxies, for instance) it will be a little difficult to find the nebula on the preview screen of the DSI. Look for a very faint patch of light, but you may have to take a few long exposures to make sure that you've found it.
Both the luminance and the color are important on M1, so be sure to devote sufficient time. Capture at least an hour of luminance and an hour per channel.
Processing the Image
Bringing out the faint tendrils at the edge of the nebula was difficult. I created different masks to allow me to process the different regions of the nebula separately.
For example, when I wanted to adjust the central core, I used the mask on the upper-left. When I wanted to enhance the edges, I used the mask in the upper-right.
