Circumhorizontal Arc Over Pilesgrove, New Jersey

July 15, 2012

LisaGChaP7110067 (2)

Photographer: Lisa Gonnelli
Summary Author: Lisa Gonnelli; Jim Foster

The photo above shows a grand circumhorizontal arc that appeared over Pilesgrove, New Jersey on July 11, 2012. From the look of the sunrise, I just knew this day was going to be a good one for observing arcs and halos. Aside from their splendid coloration, what makes these flattened arcs so special is that you can only see them, from the mid-latitudes, around midday and during the spring and summer season -- when the Sun is high in the sky (at least 57 degrees above the horizon). They form in cirrus clouds when sunlight enters though the vertical side faces of hexagonal ice crystals and exits through the lower horizontal basal faces. Make sure to protect your eyes when looking near the Sun. Photo taken at about 1:15 p.m.

Photo details: Camera Maker: OLYMPUS IMAGING CORP.; Camera Model: E-500; Focal Length: 46.0mm; Aperture: f/7.1; Exposure Time: 0.0025 s (1/400); ISO equiv: 100; Exposure Bias: none; Metering Mode: Matrix; Exposure: Creative Program (based towards depth of field); White Balance: Auto; Light Source: Unknown; Flash Fired: No (Auto); Orientation: Normal; Color Space: sRGB; Software: Adobe Photoshop Elements 8.0 Macintosh.