Subparhelion Observed Over Southeastern Brazil

December 04, 2014


Photographer: Fabiano B. Diniz; Fabiano's Flickr site
Summary Author: Fabiano B. Diniz

During a flight from Rio de Janeiro to Curitiba, Brazil, I observed an optical phenomenon known as a subparhelion. This colorful patch of light is similar to its counterpart the parhelion (sundog), but it's seldom seen. Like the sundog, ice crystals shaped like hexagonal plates and having their large faces oriented more or less horizontally are responsible for its formation. The prefix "sub" means that it's formed below the horizon. So in order to see it the observer must be above the clouds where the ice crystals reside; in a plane or on a mountain top, for instance. Photo taken on November 14, 2014.

Photo details: Camera Model: Canon EOS REBEL T3i; Lens: EF-S18-135mm f/3.5-5.6 IS; Focal Length: 135mm; Aperture: f/9.0; Exposure Time: 0.0031 s (1/320); ISO equiv: 100.