Rainbows appear when sunlight is reflected from raindrops. But in this case, the sun was not required; the Frosty Moon was bright enough to do the job on its own. "The moonlight was so bright I could see red in the rainbow with my unaided eye," says Walker. "A 30 second exposure with my digital camera revealed [the full range of rainbow colors]."

Lunar rainbows aren't the only thing you might see when the Frosty Moon is out. Be alert also for lunar coronas, moon rings, moondogs, and, last but not least, your own moon shadow.

more images: from M-P Markkanen of Kuusamo, Finland; from Ken Stenek of Shishmaref, Alaska; from Mohamad Soltanolkottabi of Kashan, Iran;

Source: Spaceweather.com