The Cygnus Loop

This large nebula is a supernova remnant in the Cygnus from a star explosion 21,000 years ago. It has a visible size of almost 3 degrees (the moon is roughly 0.5 degrees!)

(click on image for full resolution)

Lots of interesting details in this large image:

The Eastern Veil

Pickerings Triangle

The Witches Broom

The nebula is 2,400 light years from earth (the initial estimate in 1958 was 2,500 light years, it was then revised to 1,470 light years in 1999, then to 1,760 light years and most recently to 2,400).

This puts the diameter of the nebula to 130 light years and expansion rate of 60 miles per second.

This is a mosaic of two images - each having close to 30 hours imaging time. The real time to take the data was almost twice as long as I had a lot of trouble with my 10Micron mount. I think I coult finally fixed it...