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.

                                2019 January 8
                 HESS Telescopes Explore the High-Energy Sky
  Video Credit & Copyright: Vikas Chander [2] , H.E.S.S. Collaboration [3] ;
                 Music:  Emotive Piano by Immersive Music [4]

Explanation: They may look like modern mechanical dinosaurs but they are
enormous swiveling eyes that watch the sky. The High Energy Stereoscopic
System (H.E.S.S.) Observatory [5]  is composed of four 12-meter
reflecting-mirror telescopes surrounding a larger telescope [6]  housing a
28-meter mirror. They are designed to detect strange flickers of blue light --
Cherenkov radiation [7] --emitted when charged particles [8]  move slightly
faster than the speed of light [9]  in air. This light is emitted when a gamma
ray [10] from a distant source strikes a molecule in Earth's atmosphere and
starts a charged-particle shower [11] . H.E.S.S. [12]  is sensitive to some of
the highest energy photons (TeV [13] ) crossing the universe. Operating since
2003 in Namibia [14] , H.E.S.S. has searched for dark matter [15]  and has
discovered over 50 sources [16]  emitting high energy radiation including
supernova remnants [17]  and the centers of galaxies [18]  that contain
supermassive black holes [19] . Pictured last September, H.E.S.S. telescopes
swivel and stare in time-lapse sequences [20]  shot in front of our Milky Way
Galaxy [21]  and the Magellanic Clouds [22]  -- as the occasional
Earth-orbiting satellite zips by.

Open Science: Browse 1,800+ codes in the Astrophysics Source Code Library [23]

                      Tomorrow's picture: forgotten stars

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    Authors & editors: Robert Nemiroff [35] (MTU [36] ) & Jerry Bonnell [37]
                                  (UMCP [38] )
          NASA Official:  Phillip Newman Specific rights apply [39] .
              NASA Web Privacy Policy and Important Notices [40]
              A service of: ASD [41]  at NASA [42]  / GSFC [43]
                           & Michigan Tech. U. [44]
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Site notes:
  [1] archivepix.html
  [2] https://www.flickr.com/people/166147883@N04/
  [3] https://www.mpi-hd.mpg.de/hfm/HESS/pages/coll...
  [4] https://www.premiumbeat.com/artist/immersive-...
  [5] https://www.mpi-hd.mpg.de/hfm/HESS/pages/abou...
  [6] ap120727.html
  [7] https://en.wikipedia.org/wiki/Cherenkov_radia...
  [8] https://en.wikipedia.org/wiki/Charged_particl...
  [9] https://en.wikipedia.org/wiki/Speed_of_light
  [10] https://science.nasa.gov/ems/12_gammarays
  [11] ap060814.html
  [12] https://www.mpi-hd.mpg.de/hfm/HESS/pages/abou...
  [13]
https://scienceblogs.com/builtonfacts/2013/11...
how-often-does-the-sun-emit-1-tev-photons
  [14] https://en.wikipedia.org/wiki/Namibia
  [15]
https://www.nasa.gov/audience/forstudents/9-1...
what-is-dark-matter.html
  [16] http://adsabs.harvard.edu/abs/2018A%26A...612...
  [17] ap170518.html
  [18] ap180729.html
  [19] https://apod.nasa.gov/htmltest/rjn_bht.html
  [20] https://vimeo.com/302897067
  [21] ap180427.html
  [22] ap160725.html
  [23] http://ascl.net/code/all
  [24] ap190107.html
  [25] archivepix.html
  [26] lib/apsubmit2015.html
  [27] lib/aptree.html
  [28] https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apo...
  [29] calendar/allyears.html
  [30] /apod.rss
  [31] lib/edlinks.html
  [32] lib/about_apod.html
  [33] http://asterisk.apod.com/discuss_apod.php?dat...
  [34] ap190109.html
  [35] http://www.phy.mtu.edu/faculty/Nemiroff.html
  [36] http://www.phy.mtu.edu/
  [37] https://antwrp.gsfc.nasa.gov/htmltest/jbonnel...
  [38] http://www.astro.umd.edu/
  [39] lib/about_apod.html#srapply
  [40] https://www.nasa.gov/about/highlights/HP_Priv...
  [41] https://astrophysics.gsfc.nasa.gov/
  [42] https://www.nasa.gov/
  [43] https://www.nasa.gov/centers/goddard/
  [44] http://www.mtu.edu/

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