photo #5887033

A rainbow can form at night as well as in the day, because raindrops can refract and reflect the light of the Moon just as much as they do sunlight. We call the result a lunar rainbow, or a moonbow. Since moonlight is not as bright as sunlight, moonbows are always far fainter than their daytime cousins. Unless there is a bright full Moon, they tend to be too faint for us to notice them. Even when we do see them, they tend to be so pale that the photoreceptor cells in most people’s eyes cannot discern any hues at all, and so moonbows appear white to most observers. The true colours of a lunar rainbow only really shine in photographs, like this one taken by Shannon Taylor (Member 58,261) of a lunar rainbow arcing low in the sky in front of a Cumulonimbus capillatus cloud near Alameda, California, US. Shannon’s shot of a lunar rainbow reminds us that the colours of the world don’t actually disappear in the moonlight.