California Halos ~ A high sun display imaged by Alexander S Kunz (blog) in San Diego County, Southern California on 3rd March. Halos in cirrus cloud are visible the world over in all seasons

©Alexander S Kunz, shown with permission
Two halos encircle the 47° high sun.

The inner truly circular one is the familiar 22° radius halo.

The outer considerably less circular is the circumscribed halo. It touches the 22° halo above and below the sun. When the sun is less than 29° high it splits into upper and lower tangent arcs. Horizontal hexagonal column crystal generate it. At very high sun it becomes almost circular and is often mistaken for the more pastel coloured 22° halo.

A bright parhelic circle crosses the sun. It is parallel to the horizon. In the HaloSim ray tracing at right the fisheye projection makes it appear to curve upwards.

The sundogs or "22° parhelia" are far away from 22° from the sun. Sundogs are only at that distance when the sun is on the horizon.

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