Corona and Conifer
December 18, 2002
On the photo above, the conifer in the foreground appears to be adorned by a corona - a nice touch for the holidays. This is a wonderful example of a solar corona. Coronae are formed in clouds when light diffracts or scatters through microscopic water droplets of a uniform size. This produces interference rings that results in the colorful concentric circles around the Sun or Moon. Coronae form very close to an illumination source, unlike halos, which are usually no closer than 22 degrees from the Sun or Moon. Note that coronae colors go outward from white to blue, to green, to yellow, and to red in repeating series.