The moon’s ever changing appearance is free to all that take the time to be mesmerized by the night sky. The simple beauty of the moon is one of nature’s many splendid treasures. When conditions are right the moon can produce interesting optical effects, the most common of which is a moon halo. A lunar halo or rings around the moon are an optical atmospheric phenomenon that happens with the moon. Halos are caused by tiny ice crystals that have gathered twenty thousand feet above the ground, as thin, wispy clouds. These clouds are so thin if it weren't for their effect on the moonlight, you might not notice them at night. Incoming light rays from the moon are bent--or "diffracted"--by these ice crystals at an angle of twenty-two degrees. This means that in addition to the direct moonlight, you will also see diffracted moonlight in a circle twenty-two degrees away from the moon. This is about the distance of your fist, held at arm's length. According to Folklore, a moon halo is a sign that bad weather is on the way. There may be some truth to this since the halo is usually caused by high-altitude cirrus clouds that precede a warm front. Typically, a warm front will be associated with a low-pressure system which is commonly referred to as a storm. Some believe that the number of stars within a moon halo indicates the number of days before bad weather will arrive and some believe the number of stars indicate the number of days a winter storm will last.