Ringblitz

Ringblitz is a term used in the field of astronomy to describe a phenomenon where a bright ring of light appears around the Moon. This optical effect is caused by the refraction of light through ice crystals in high-altitude cirrus clouds. The ring is typically seen when the Moon is high in the sky, and it appears as a faint, circular halo with a radius of about 22 degrees. The ringblitz is often accompanied by other optical phenomena, such as parhelia (sundogs) and circumzenithal arcs, which are also caused by the refraction of light through ice crystals. The term "Ringblitz" is derived from the German words "Ring" (ring) and "Blitz" (lightning), reflecting the sudden appearance of the ring of light around the Moon. The ringblitz is a relatively rare phenomenon, but it can be observed under the right conditions, typically during the winter months when cirrus clouds are more common.