I've witnessed the moon halo twice - two years ago and yesternight at 1:00 a.m. Unfortunately, I lacked the camera to capture the moment on both occasions. :(
Halo is an optical phenomenon that appears as a ring of coloured or white light surrounding the sun or moon. It is commonly known as 22-degree halo by scientists.
Halos form when light from the sun or moonlight is refracted by ice crystals in the atmosphere.