Coronae are colored concentric rings circling within a few degrees of the Sun or Moon and are caused by diffraction of light in water droplets. Tiny water droplets, or more rarely ice crystals in clouds, may impede light rays and produce interference rings. The size of the rings depends not only on the wavelength of light but on the size of the droplets or crystals - smaller droplets produce larger rings. Coronae colors progress from white in the middle (an aureole) to blue, green, yellow and red, and this series repeats outward for each successive ring.

In sunlight, and in the antisolar direction, colorful 'Glories' (not shown here) are seen around the observers shadow, also with aureole rings. These are also known as the Spectre of Brocken. The name is derived from sightings on the 'Brocken', the highest peak of the Harz Mountains in Germany.