♦ This phenomenon is commonly referred to as the 22-degree circular halo of the sun, or sometimes called the moon (also called moon ring or winter halo), occurs when the sun’s or moon’s rays are deflected/refracted through hexagonal ice crystals found in cirrus clouds
♦ This is also known as the Kaleidoscopic Effect.
♦ These halos are known as 22-degree halos because the halo or ring has an apparent radius of 22 degrees around the sun/moon.
♦ Cirrus clouds, which are thin, detached, hair-like clouds, produce circular halos in particular. These clouds form at a height of more than 20,000 feet in the atmosphere.
♦ A halo, like a rainbow, is visible when viewed from the right angle, sometimes appearing only white but often with colours from the spectrum clearly visible.
♦ The halo is brightest at the circular disk’s inner edge, with no light inside the disc because no light is refracted at smaller angles.
♦ Red light has less refraction than other colors, so the inner edge of the halo appears red. Other shadows usually overlap and wash off.