Atmospheric corona around the moon, photographed above Cochem castle and Moselle river at dusk from the town of Cochem, Germany. The Imperial Castle of Cochem (Reichsburg) dates back to the 11th century or earlier sits about 100 meters above the town. A corona may be seen when thin clouds partially veil the sun or moon. Coronae have an intensely bright white central aureole fringed with yellows and reds. Sometimes it has one or more successively fainter and gently colored soft rings surrounding the aureole.