April - flowers You are here: Home Photo gallery Atmospheric optics Ice crystal halos Parhelic circle


The parhelic circle can be an impressive white arc spanning 360 degrees in azimuth when complete, running through the sun, the two 22o parhelia, the two 120o parhelia and the anthelion. It is parallel to the horizon, and at the same elevation as the sun. The parhelic circle is caused by sunlight reflecting from the vertical faces of horizontally aligned, plate-like ice-crystals. Sometimes, the arc can also be colored, in the anthelion area, due to a more complex light path actually through the plate crystals. The first three photos in this gallery show this coloring.

10 photos in gallery
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