Moon glory (circular rainbow) and Brocken pectre (centre left) shadow seen from Miradouro do Ujo across the Tua Valley, Portugal. A glory is an optical phenomenon produced by the backscattering of light towards its source by a cloud of large water droplets. Backscattering is the combination of diffraction, reflection and refraction. A glory is seen in the direction opposite the sun. A Brocken spectre, or Brocken bow, is the apparently enormous magnified shadow of an object cast upon the upper surfaces of clouds opposite the sun.