Lunar Corona Over Nanaimo, British Columbia
May 08, 2005
The above photo showing a superb lunar corona was taken from Nanaimo, British Columbia, just after midnight on January 23, 2005. I snapped this picture of the Moon simply because it looked so unusual -- I had never seen such colors or such an array of lunar rings. It's actually a good representation of how the Moon appeared that night.
Unlike halos, which are composed of ice crystals, coronae are concentric rings circling within a few degrees of the Sun or Moon. They're caused by diffraction of light in cloud water droplets, which impede light rays an on occasion produce interference rings. The size of the rings depends not only on the wavelength of light but on the size of the droplets -- very fine droplets produce larger rings and vice versa. Coronae coloration is generally faint. The colors progress from white in the middle to blue, green, yellow and red, and this series repeats outward for each successive ring.Related Links: