Subsun and Halo
March 04, 2003
As the audience looks out through the window of a high-flying airplane, dancing ice crystals mount a variety show on the stage of the sky. Sunlight refracted through randomly oriented, hexagonal crystals in the clouds forms the lower part of the 22-degree halo, which is centered around the Sun (off the top of the photo). Down below is a bright subsun caused by reflection from the crystals' upper surfaces. Pencil-shaped crystals floating more or less parallel to the ground create a faint elongated enhancement at the bottom of the halo, connecting these phenomena.