Sun plus ice equals nice!Douglas County residents were treated to a visual treat Tuesday morning. Sundogs added a pallet of bright color to the sunrise. Several Echo Press readers e-mailed us photos of the phenomena. What exactly are sundogs?
By: Al Edenloff, Alexandria Echo Press
Douglas County residents were treated to a visual treat Tuesday morning.
Sundogs added a pallet of bright color to the sunrise.
Several Echo Press readers e-mailed us photos of the phenomena.
What exactly are sundogs?
They’re bright splotches of light on the horizon that look like false suns. They get their name because they accompany the sun.
“Astro Bob,” a blogger on the Echo Press website, explained that sundogs, often seen in pairs at a 22-degree angle to the sun, are formed by light refracting through hexagonal, plate-shaped crystals, the broad sides of which are parallel to the ground.
There are names for other images that are often seen with sundogs. Astro Bob outlined them:
• Sun pillar – the spike of light sticking up from the sun.
• Halos — arcs of light that sometimes can be seen in the sky over the sundogs. The smaller halo is a common 22-degree variety caused by light refracted or bent through billions of randomly-oriented, hexagonal ice crystals shaped like stubby pencils. A much rarer, larger ring called a 46-degree halo, forms when light passes through the side faces of randomly oriented, pencil-shaped crystals.
• Upper tangent arc – a bright spot atop the smaller halo formed when light passes through the side faces of pencil crystals with their long sides parallel to the ground.
• Parhelic circle – a faint arc that sometimes can be seen passing through the sundogs and continuing beyond. This unusual phenomenon happens when light is reflected mirror-like from the vertical faces of several different varieties of ice crystals.
In a less scientific vein, sundogs are believed to signal a change in the weather, indicating that snow is on the way. But, like the weather forecasts, they’re not always accurate.