SUNDOG SCIENCE

A sun dog or sundog (scientific name parhelion, plural parhelia, for "beside the sun") is an atmospheric optical phenomenon primarily associated with the reflection or refraction of sunlight by small ice crystals making up cirrus or cirrostratus clouds. Often, two sun dogs can be seen (one on each side of the sun) simultaneously.

Sundog, Fargo ND, Public Domain photo.

The production of sundogs requires the presence of clouds of ice crystals in the atmosphere. When sunlight passes through the sides of a flat ice crystal, both the angle of the sun rays and the orientation of the crystals affects the shape and color of the sun dogs. Misaligned or wobbling crystals produce colourful and elongated sun dogs, while light passing through the crystal in non-optimal deviation angles (up to 50°) produces the "tail" of the sun dog stretching away from the sun. As refraction is dependent on wavelength, the sun dogs tend to have red inner edges while the colours farther from the sun tend to be more bluish-white as colours increasingly overlap. When the sun is low, the two sun dogs are located on the circle of the 22° halo. As the sun rises, the sun dogs slowly move along the parhelic circle away from the sun, finally to vanish as the sun reaches 61° over the horizon.

Antarctica, South Pole Station, Date: January 1979, Photoby: Commander John Bortniak, NOAA Corps. This image is in the public domain because it contains materials that originally came from the U.S. National Oceanic and Atmospheric Administration, taken or made during the course of an employees official duties.

Sundogs appear many times in literature,and in movies and plays. Shakespeare also appears to mention the phenomenon in his Henry VI, Part 3 when he has Edward say, Dazzle mine eyes, or do I see three suns?Sun dogs appear in the film The Deer Hunter. At the beginning of the film, as the men are leaving work, they see the phenomenon. Robert De Niro's character describes it as an old Indian thing and A blessing on the hunter sent by the great wolf to his children.

This image is in the public domain because it contains materials that originally came from the U.S. National Oceanic and Atmospheric Administration, taken or made during the course of an employees official duties.

Legend and folklore: Several tales of the appearance of sundogs have existed in popular culture. Some say a sundog brings good luck when spotted on a long journey, others say it will bring a radical change in weather conditions, such as rain. Amazingly, like many types of weather folklore, there may be some truth to the tales. Before the advent of modern technology, people often explained the weather in the easiest way possible...by talking about it! Making rhymes, sayings, and predictions about the weather was (in a way) an early form of weather broadcasting. How to Safely View Sundogs: Usually, a pair of glasses with polarizing lenses is required, both to protect the eyes and to render the atmospheric effects visible.

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