Veil nebula, a supernova remnant in Cygnus, here in its entirety, from the eastern arc at left, catalogued as NGC 6992/5, to the western arc at right, NGC 6960, running past the star 52 Cygni. At top is the wedge-shaped Pickering's Triangle. The field is filled with lots of little nebula, all of which are the remains of a star that exploded as a supernova some 10,000 to 20,000 years ago and located about 2,400 light years away. The red is emission from ionized hydrogen, the cyan emission from ionized oxygen. This nebula shows a lot of oxygen emission at the leading edge of the expanding cloud of debris.