.Cygnus Loops star Discs for the Homestar Flux. The Cygnus Loop is a large supernova remnant in the constellation Cygnus, and measures nearly 3° across. Some arcs of the loop, known collectively as the Veil Nebula or Cirrus Nebula, emit in the visible electromagnetic range. Radio, infrared, and X-ray images reveal the complete loop. This disc will NOT fit other brands for home planetariums