Parhelic Arc Over Caen, France
November 11, 2012
Photographer: Rudolf Wehrung; Rudolph's Web site
Summary Authors: Rudolf Wehrung; Jim Foster
The photo above shows a portion of a parhelic arc (at right center) as observed near Caen, France on September 3, 2012. Note that the Sun is behind the camera. Many times fascinating arcs, halos and/or bows accent the sky but they are rarely seen by most people. Now and then, the colors of some of these features are breathtaking, circumzenithal and circumhorizon arcs, for example. However, more often than not they portray unremarkable coloration or are, in fact, colorless and easily blend in with clouds or contrails. Parhelic arcs are such features. They result when sunlight reflects off the vertical faces of plate-shaped ice crystals in cirrus clouds and are found at the same elevation as the Sun. On rare occasion, they completely encircle the sky. Anytime cirrus clouds are visible, parhelic arcs may be seen as well -- it's worth taking a look.