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Circumscribed Halo

Imaged by Marion Glas during the recent intense halo display over The Netherlands.

The inner circular halo is the familiar 22° halo. A faint parhelic circle cuts across it and the sun.

The outer baggy halo is the circumscribed. It is tangent to the 22° halo directly above and below the sun

Image ©Marion Glas

At sunrise there are symmetrical upper and lower tangent arcs. As the sun climbs the upper one's wings increasingly droop low over the 22° halo.

Come 29° and the tangent arcs fuse into the circumscribed halo. It tightens around the 22° halo and at high sun the two can be hard to distinguish.

Singly oriented column crystals make it.