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Астронет: Астрономическая картинка дня Езда навстречу солнечному гало http://www.variable-stars.ru/db/msg/1214465/eng |
Credit & Copyright: Lauri Turtiainen
Explanation:
What's happened to the Sun?
Sometimes it looks like the Sun is being viewed through a large
lens.
In the above case, however, there are actually millions of lenses:
ice crystals.
As water freezes in the upper
atmosphere, small, flat, six-sided, ice crystals might be formed.
As these crystals flutter to the ground, much time is spent
with their faces flat, parallel to the ground.
An observer may pass through the same plane as
many of the falling ice crystals near sunrise or sunset.
During this alignment, each crystal can act like a miniature lens,
refracting sunlight into our view and creating
phenomena like parhelia, the technical term for
sundogs.
The above image was taken during early 2006 February near
Helsinki,
Finland
with a quickly deployed cellular
camera phone.
Visible in the image center is the Sun, while two bright
sundogs glow prominently from both the left and the right.
Also visible is the
22 degree halo also created by
sunlight reflecting off of atmospheric ice crystals.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.