Friday, January 8, 2010

Diamond Dust Sundogs


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Coming home from grocery shopping last evening I spotted sundogs on each side of the setting sun.  Also called "mock suns" the scientific name is parahelia.  Sundogs appear as colored patches of light 22 degrees on each side of the sun and are formed by ice crystals in very cold high cirrus clouds or from "diamond dust" crystals drifting in the air at low levels.  This was probably diamond dust because the wind was blowing the fine particles of snow into the air.  The temperature was about 7 degrees Farenheit.

Also notice the dark beam shooting out of the left side of sun.  This is another atomospheric phenomenon called a crepuscualr ray, which is just a shadow of the cloud near the sun's position.


Click on image for a larger view
About a month ago, my nephew, Ambrose Solis, captured this bright sundog with his camera phone in Colorado.  This one was definitely caused by ice crystals in the high cirrus clouds.

Sometimes sundogs are accompanied by various arcs and halos, also caused by ice crystals.  Be on the look out for sky phenomon such as these.  They even occur in the Summer time and can easily be photographed with the simplest camera.

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