An optical phenomenon resulting from the refraction and reflection of moonlight within ice crystals in cirrus or cirrostratus cloud; also known as a mock Moon. It is the lunar equivalent of the parhelion. Parselenae appear 22° from the Moon and at the same altitude as the Moon above the horizon. They occur only when the Moon is bright, typically within five days of full. Being fainter than parhelia, they are usually colourless to the naked eye.