Astronomy Picture of the Day

                         Astronomy Picture of the Day

    Discover the cosmos! [1] Each day a different image or photograph of our
 fascinating universe is featured, along with a brief explanation written by a
                           professional astronomer.

                               2018 December 21
                                      [2]
                          Extraordinary Solar Halos
               Image Credit & Copyright [3] : Magnus Edback [4]

Explanation: Welcome to the December Solstice, the first day of winter in
planet Earth's northern hemisphere and summer in the south. To celebrate,
consider this extraordinary display of beautiful solar ice halos! More common
than rainbows [5] , simple ice halos can be easy to spot, especially if you
can shade your eyes from direct sunlight. Still it's extremely rare to see
anything close to the complex of halos [6] present in this astounding scene.
Captured at lunchtime [7] on a cold December 14 near Utendal, Sweden the image
includes the relatively ordinary 22 degree halo, sundogs (parhelia) and sun
pillars. The extensive array of rarer halos [8]  has been identified along
with previously unknown features. All the patterns are generated as sunlight
(or moonlight) [9]  is reflected and refracted in flat six-sided water ice
crystals in Earth's atmosphere. In this case, likely local contributors to the
atmospheric ice crystals are snow making machines operating at at nearby ski
center.

                      Tomorrow's picture: pixels in space

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    Authors & editors: Robert Nemiroff [21] (MTU [22] ) & Jerry Bonnell [23]
                                  (UMCP [24] )
          NASA Official:  Phillip Newman Specific rights apply [25] .
              NASA Web Privacy Policy and Important Notices [26]
              A service of: ASD [27]  at NASA [28]  / GSFC [29]
                           & Michigan Tech. U. [30]
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Site notes:
  [1] archivepix.html
  [2] image/1812/IMG_8741_cSunHaloEdback2048.jpg
  [3] lib/about_apod.html#srapply
  [4] https://www.astrobin.com/users/Magnusedback/
  [5] https://science.nasa.gov/science-news/science...
2002/24oct_sunrings
  [6] https://www.atoptics.co.uk/halosim.htm
  [7] http://www.thehalovault.org/2018/12/
complex-halo-display-borlange-sweden.html
  [8] https://www.atoptics.co.uk/fza164.htm
  [9] ap150403.html
  [10] ap181220.html
  [11] archivepix.html
  [12] lib/apsubmit2015.html
  [13] lib/aptree.html
  [14] https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apo...
  [15] calendar/allyears.html
  [16] /apod.rss
  [17] lib/edlinks.html
  [18] lib/about_apod.html
  [19] http://asterisk.apod.com/discuss_apod.php?dat...
  [20] ap181222.html
  [21] http://www.phy.mtu.edu/faculty/Nemiroff.html
  [22] http://www.phy.mtu.edu/
  [23] https://antwrp.gsfc.nasa.gov/htmltest/jbonnel...
  [24] http://www.astro.umd.edu/
  [25] lib/about_apod.html#srapply
  [26] https://www.nasa.gov/about/highlights/HP_Priv...
  [27] https://astrophysics.gsfc.nasa.gov/
  [28] https://www.nasa.gov/
  [29] https://www.nasa.gov/centers/goddard/
  [30] http://www.mtu.edu/

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