Parry Arc Over Budapest
July 31, 2007
On the photo above, taken from Budapest, Hungary, both an upper tangent arc and the rarer Parry arc can be detected (both are rather faint). A Parry arc is an arc of light sometimes seen above or below the 22 degree solar halo. It's mainly observed at sun elevations between 15 and 40 degrees. The arc is named for Sir William Edward Parry who described the phenomenon as seen during an Arctic expedition in 1820.
These glorious arcs were first noticed when the Sun was approximately 20-25 degrees above the horizon. The upper Parry arc is concave downward. Hexagonal ice crystals in cirrus fibratus and cirrostratus clouds, which were in the vicinity of the Sun much of the day, allowed us to also see the 22 degree halo, sundogs, the parhelic circle, and circumzenithal arc. Photo taken on March 5, 2007.