Ireland Halos
Captured by Peter Otoole at Letterkenny, County Donegal, Ireland on Sunday June 20.

Images ©Peter Otoole, shown with permission.

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Refraction through randomly oriented hexagonal ice crystals made the steeply sloping band of colour � a 22 degree ice halo fragment. At its centre and barely distinguishable from it shines a weak sundog with a hint of bluish tail.

22 degree halos and sundogs always have red sunwards � the sun is off image to the right.

At right a contrail imprints its dark shadow onto lower cloud. The convolved clouds around the halos suggest that their icy crystals grew from the newly minted water vapour of aircraft engines.