Other forms: moonbows
A moonbow is a natural phenomenon that occurs when moonlight is refracted, reflected, and dispersed through water droplets in the air. To the naked eye, it appears like a faint white or silvery arc in the night sky.
A moonbow is like a regular rainbow, but because moonlight is much dimmer than sunlight, it appears fainter, and our eyes usually can't perceive the full spectrum of colors. Long-exposure photographs, however, can reveal those colors. Moonbows are relatively rare. They require a bright, full or nearly full moon that is low in a dark sky, along with rain or mist opposite the moon. Places with misty waterfalls, such as Yosemite Falls in California and Victoria Falls in Africa, are great places to see moonbows.