July - lightning You are here: Home Photo gallery Atmospheric optics Ice crystal halos 23o parhelion

A parhelion, usually in the form of a piece of arc, about 23o above and below the sun, caused by refraction of light by oriented, pyramidal ice crystals. They can easily be confused with parry arcs; when I took the photos below any confusion was ruled out because the sun was too high in the sky for the upper Parry arcs to appear separated from the 22o halo, and other odd-radius halos and parhelia which form in the same type of ice crystals were present.

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