Supralateral Arc

The supralateral arc is fairly rare in this country, partly because the large area of sky that it covers means a very extensive veil of suitable ice crystals is needed. This display showed more than half the arc.

A composite of four images shows a fairly bright inner 22 degree halo and the weaker, but more colourful, supralateral stretching down from near the top into the gap in the trees on the right.

(The broad greenish area between the arcs is a processing artefact)

Three of the individual frames show the arc a bit more clearly. Although there was a weak upper tangent arc at the top of the 22 degree halo there was no sign of a circumzenthal arc, which would have been at the top of the supralateral arc.

Canon EOS 20D   29th April 2009
Wiltshire, England

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