Circumzenithal and Upper Tangent Arcs
October 22, 2005
The above photo showing a splendid circumzenithal arc and a more timid upper tangent arc was taken on August 27, 2005 over Erlensee, Germany. Thanks to the presence of oriented ice crystals in cirrus clouds, this day proved a fine one for observing halo phenomena. In the morning, I was able to see a circumscribed halo, but in the afternoon this was topped by the appearance of sundogs (parhelia), a circumzenithal arc and an upper tangent arc (lower center of photo). These bands and patches of colored light graced the sky for more than three hours, allowing me the chance to point them out to folks visiting an exhibition on historic farm machines.