The Veil Nebula

2 Panel mosaic of the veil nebula complex in the Cygnus loop in HOO and SHO palette.

Veil nebula is a supernova remnant, many portions of which have acquired their own individual names and catalogue identifiers. The source supernova was a star 20 times more massive than the sun which exploded between 10,000 and 20,000 years ago. At the time of explosion, the supernova would have appeared brighter than Venus in the sky, and visible in daytime. The remnants have since expanded to cover an area of the sky roughly 3 degrees in diameter about 6 times the diameter, and 36 times the area, of the full Moon - Source Wikipedia