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            Moondogs caught
                by David Cartier (images)
              near midnight on December 26, '07 above Snag, Yukon Territory,
              Canada .
              The display, which includes parts of of a paraselenic (lunar
              parhelic) circle,
              22 degree halo, lower pillar and submoon was
              created by diamond
              dust in the -40F air. Snag lies  in a hollow formed by the
              White River and tributaries, a good location for diamond dust formation.
              Praktica VLC3 35mm Camera, 16mm Zenitar lens, 15 second exposure
              on Fuji Natura 1600 film. Image ©David
              Cartier, shown with permission.  
               
              The moon forms halos just like the sun. Its equivalent of sundogs
              are called paraselenae or parselenae. Lunar halos 
              are intrinsiclly faint and to see them dark surroundings and
              a near full moon are best. Visually they often appear colourless
              or almost so because their light is not strong enough to excite
              the colour sensors in our eyes.  | 
           
       
         
         
       
       
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