If you didn't know what a moonbow is, I'm sure you'll get it just at the moment you'll see the picture sent to us by Windy user, captain Serge Prakhov (Thank you, captain Prakhov!).
A moonbow (also known as a lunar rainbow or white rainbow) is a rainbow produced by moonlight rather than sunlight.
A moonbow often appears to be white because the light is usually too faint to excite our cone color receptors. Still, you can capture the colors in a moonbow on a film or digital camera set to a longer exposure.
Same as a solar rainbow, moonbow's formation is caused by the refraction of light in water droplets and it is always positioned in the opposite part of the sky from the moon relative to the observer.
This weather phenomenon is known at least since Aristotle's Meteorology circa 350 BCE.
Moonbow at Pacific Ocean, 10 May 2017, Serge Prakhov