On Christmas Eve 1996, a spectacular sight occurred in the Colorado sky over Boulder. This did not involve flying reindeer, but with its vivid red and green colors did seem appropriate to the holiday season. As the last Christmas Eve full moon of this century passed behind a thin wave cloud, formed by the wind blowing from west to east over the Rocky Mountains, the small, uniform cloud droplets produced the most colorful lunar corona I have ever seen. My children, who have learned to notice optical phenomena in the sky, pointed it out to me, successfully delaying their bedtime another hour while we took photographs.
by Joseph A. Shaw