Moonbow

The New Year began with a spectacular sighting - a moonbow rising out of the sea before daybreak with an almost full moon in the western sky.

Moonbows are rare because moonlight is not very strong. A bright moon near to full is needed; it must be raining opposite the moon; the sky must be dark and the moon must be less than 42º high. If we put all these conditions together, it is no surprise that moonbows or lunar rainbows are not such a common occurrence. They are also known as white rainbows because normally their light is not bright enough to activate the cone colour receptors in our eyes.

Let's hope that this unusual sighting is a sign of what the New Year has in store!