Subtle Lunar Corona
October 12, 2003
The above photo of a tenuous lunar corona, was captured near the time of the Full Moon last December, above Memphis, Tennessee. Coronae result from diffraction of light. Minute water droplets in clouds may interfere with light rays and produce interference rings. The size of the rings depends not only on the wavelength of light but also on the size of the droplets - smaller droplets produce larger rings. Unlike halos, with coronae the rings of light are very near to the Moon or Sun. It was noticed that the delicate colors associated with this corona expanded and contracted as the thickness of the cloud deck changed. See the Earth Science Picture of the Day for March 3, 2003 and for February 6, 2002.