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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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