The Western Veil, NGC 6960, commonly named The Witch's Broom, is part of the Veil Nebula, which is also known as the Cygnus Loop. The Veil nebula is located in the constellation, Cygnus, at a distance of about 1400 light-years. Its apparent size is more than five times the full Moon.
The Veil Nebula is a supernova remnant of heated and ionized gas. The source supernova exploded some 10,000 to 20,000 years ago. The expanding debris cloud gains its colors by sweeping up and exciting existing nearby gas.
Although this image was taken with narrow band filters it is a fairly good presentation of what the nebula looks like if red, green and blue filters were used. This is possible because the band width of the OIII filter is about half way between green and blue. This technique works especially well with this nebula because the RGB colors are mostly red and cyan. I used this method because, with true RGB, the stars completely overwhelm the nebula. Using narrowband filters also reveals greater detail.
Taken with an SBIG STL-11000 camera, using Astrodon filters and an
RCOS 12.5" scope.
Synthetic color, (Ha:OIII:OIII mapped to r,g & b), with LRGB stars overlayed
Ha 540 min (18 x 30 min)
OIII 540 min (18 x 30 min)
Lum 465 min (16 x 15 min)
RGB 270 min ( 6 x 15 min)
Original size = 3825 x 2550
For more info and a larger view see...