A colorful lunar corona photographed over Cochem Castle (Reichsburg, from the 12th century) in Germany. The corona is formed as bright moonlight is diffracted by water droplets in thin clouds drifting in front of the lunar disk. This atmospheric phenomena have an intensely bright central aureole which is white-blue and fringed with yellows and reds. The corona can be 15 degrees or so in diameter and often it shrinks and swells as different clouds move in front of the moon.