Solar Halo Over Famões, Portugal

July 12, 2015

Solar_haloIMG_5441-ES (1)

Photographer: Nuno Lopes 
Summary Authors: Nuno Lopes; Jim Foster
Shown above is a glorious 22 degree solar halo observed over a spring meadow near Famões, Portugal (just north of Lisbon). Halos such as this form when sunlight is refracted by hexagonal ice crystals that compose cirrus clouds. Sunlight enters one of the crystal's side faces and exits through an alternate face at a 22 degree angle. If the crystals are smaller than about 0.025 mm in diameter, they tend to be randomly oriented and thus produce a ring of light around the solar disk. Make sure to protect your eyes when looking anywhere near the Sun. Photo taken on April 23, 2015.
Photo Details: Camera Model: Canon EOS 550D; Lens: EF-S10-18mm f/4.5-5.6 IS STM; Focal Length: 10mm; Aperture: ƒ/11.0; Exposure Time: 0.0013 s (1/800); ISO equiv: 200; Software: Adobe Photoshop Lightroom 5.6 (Windows).