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 October 27
                                      [2]
                              Airglow Borealis
  Image Credit & Copyright [3] : Yuri Beletsky [4] (Carnegie [5] Las Campanas
                         Observatory [6] , TWAN [7] )

Explanation: The best known [8] asterism in northern skies hangs over the
Canadian Rockies in this mountain and night skyscape taken last week from
Banff National Park. But most remarkable is the amazing greenish airglow. With
airglow visible to the eye, but not in color, the scene was captured [9]  in
two exposures with a single camera, one exposure made while tracking the stars
and one fixed to a tripod. Airglow emission is predominately from atmospheric
oxygen atoms at extremely low densities. Commonly recorded in color by
sensitive digital cameras the eerie, diffuse light is seen here in waves
across [10] the northern night. Originating at an altitude similar to aurorae,
the luminous airglow is due to chemiluminescence [11] , the production of
light through chemical excitation and radiative decay. Energy for the chemical
excitation is provided during daytime by the Sun's extreme ultraviolet
radiation [12] . Unlike aurorae which are limited to high latitudes [13] ,
airglow can be found around the globe [14] .

                    Tomorrow's picture: lunar observatory

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    Authors & editors: Robert Nemiroff [26] (MTU [27] ) & Jerry Bonnell [28]
                                  (UMCP [29] )
          NASA Official:  Phillip Newman Specific rights apply [30] .
              NASA Web Privacy Policy and Important Notices [31]
              A service of: ASD [32]  at NASA [33]  / GSFC [34]
                           & Michigan Tech. U. [35]
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Site notes:
  [1] archivepix.html
  [2] image/1810/airglow_banff_beletsky.jpg
  [3] lib/about_apod.html#srapply
  [4] https://www.instagram.com/yuribeletsky/
  [5] http://carnegiescience.edu/
  [6] http://www.lco.cl/
  [7] http://www.twanight.org/
  [8] ap170407.html
  [9] https://www.instagram.com/p/BpPkecTlf22/
  [10] https://www.atoptics.co.uk/highsky/hgrav.htm
  [11] http://www.atoptics.co.uk/highsky/airglow2.ht...
  [12] https://science.nasa.gov/ems/10_ultravioletwa...
  [13] ap181006.html
  [14] ap160331.html
  [15] ap181026.html
  [16] archivepix.html
  [17] lib/apsubmit2015.html
  [18] lib/aptree.html
  [19] https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apo...
  [20] calendar/allyears.html
  [21] /apod.rss
  [22] lib/edlinks.html
  [23] lib/about_apod.html
  [24] http://asterisk.apod.com/discuss_apod.php?dat...
  [25] ap181028.html
  [26] http://www.phy.mtu.edu/faculty/Nemiroff.html
  [27] http://www.phy.mtu.edu/
  [28] https://antwrp.gsfc.nasa.gov/htmltest/jbonnel...
  [29] http://www.astro.umd.edu/
  [30] lib/about_apod.html#srapply
  [31] https://www.nasa.gov/about/highlights/HP_Priv...
  [32] https://astrophysics.gsfc.nasa.gov/
  [33] https://www.nasa.gov/
  [34] https://www.nasa.gov/centers/goddard/
  [35] http://www.mtu.edu/

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