Cygnus Loop The Cygnus Loop (radio source W78, or Sharpless 103) is a large supernova remnant (SNR) in the constellation Cygnus, an emission nebula measuring nearly 3° across.[1] Some arcs of the loop, known collectively as the Veil Nebula or Cirrus Nebula, emit in the visible electromagnetic range.[1] Radio, infrared, and X-ray images reveal the complete loop. Backyard image with Stellarvue 80mm Access refractor@f5.6, ZWOASIO71 P, Skywatcher E6R-Pro mount
