vThe Veil Nebula is a cloud of heated and ionized gas and dust
in the constellation Cygnus. It constitutes the visible portions
of the Cygnus Loop (radio source W78, or Sharpless 103), a large
but relatively faint supernova remnant. The source supernova exploded
some 5,000 to 8,000 years ago, and the remnants have since expanded to
cover an area roughly 3 degrees in diameter (about 6 times the diameter,
or 36 times the area, of the full moon). The distance to the nebula is
not precisely known, but Far Ultraviolet Spectroscopic Explorer (FUSE)
data supports a distance of about 1,470 light-years.

The Hubble Space Telescope captured several images of the nebula. The
analysis of the emissions from the nebula indicate the presence of
oxygen, sulfur, and hydrogen. This is also one of the largest, brightest
features in the x-ray sky.