Halo Sky

The 22-degree moon halo is photographed in this wide-angle view from Hungary. Large atmospheric halo around the Moon or the sun occurs when high thin clouds containing millions of tiny ice crystals cover much of the sky. Each ice crystal acts like a miniature lens. Because most of the crystals have a similar elongated hexagonal shape, light entering one crystal face and exiting through the opposing face refracts 22 degrees, which corresponds to the radius of the Sun or the Moon Halo.