Alaskan Moondogs

Moonlight illuminates a snowy scene, surrounded by an icy halo and flanked left and right by moondogs, in this night land and skyscape made on January 17 from Lower Miller Creek, Alaska, USA.   Image © Sebastian Saarloos.    Used with permission.

Larger image

Overexposed near the mountainous western horizon is the first quarter Moon. Sometimes called mock moons, a more scientific name for the luminous apparations is paraselenae (plural).

Like the sundog or parhelion, a paraselene is produced by moonlight refracted through thin, hexagonal, plate-shaped ice crystals in high cirrus clouds. As determined by the crystal geometry, paraselenae are seen at an angle of 22 degrees or more from the Moon. Compared to the bright lunar disk, paraselenae are faint and easier to spot when the Moon is low.

source Apod