This is the eastern portion of the Veil Nebula (NGC6992), or Cygnus Loop, a supernova remant. The supernova exploded 5,000 to 8,000 years ago, and the remnants have been expanding ever since. The distance to the Veil nebula isn’t well known, estimates range from 1,400 to 2,600 light years. The Veil Nebula is part of the Cygnus loop. which covers an area 3 degrees across in the sky. That’s six times the diameter of the moon.