Thursday, 21 August 2008
Two high-sun Parry arcs
In the above image, we can see an almost straight-looking Parry arc photographed by Faber McMullen at 69° sun altitude. The image was taken in Navasota, Texas, on 8 May 2008. The Parry arc was accompanied by a circumscribed halo, and a parhelic circle that is faintly present in the pictures, too ( 1 ). He also made a simulation with Les Cowley’s and Michael Schroeder’s HaloSim, which helps to interpret the photo ( 2 ).
The other observation comes from Holesov, Czech Republic. Patrik Trncak photographed a short-lived Parry arc at 61° sun altitude on 19 June ( 3 ). The circumstances were similar. The cirrus clouds produced a circumscribed halo and a full parhelic circle besides the Parry arc.