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 18
                                      [2]
                        Cherenkov Telescope at Sunset
  Image Credit & Copyright [3] : Sarah Brands [4]  (University of Amsterdam)

Explanation: On October 10, a new telescope reflected the light of the setting
Sun. With dark horizon above and sunset colors below, its segmented mirror
inverts an image of the beautiful evening sky in this snapshot from the Roque
del Los Muchachos Observatory on the Canary Island of La Palma. The mirror
segments cover a 23 meter diameter and are mounted in the open structure of
the Large Scale Telescope 1 [5] , inaugurated as the first component of the
Cherenkov Telescope Array (CTA). [6] Most ground-based telescopes are hindered
by the atmosphere that blurs, scatters, and absorbs light. But cherenkov
telescopes are designed to detect very high energy gamma rays [7] and actually
require the atmosphere to operate. As the gamma rays impact the upper
atmosphere they produce air showers [8]  of high-energy particles. A large,
fast camera at the common focus images the brief flashes of optical light,
called Cherenkov light [9] , created by the air shower particles. The flashes
reveal the incoming gamma ray timing, direction, and energy. Ultimately more
than 100 Cherenkov telescopes are planned for the CTA at locations in both
northern and southern hemispheres on planet Earth [10] .

                     Tomorrow's picture: winter is coming

-------------------------------------------------------------------------------
< [11] | Archive [12] | Submissions [13] | Index [14] | Search [15] | Calendar
  [16] | RSS [17] | Education [18] | About APOD [19] | Discuss [20] | > [21]
-------------------------------------------------------------------------------

    Authors & editors: Robert Nemiroff [22] (MTU [23] ) & Jerry Bonnell [24]
                                  (UMCP [25] )
          NASA Official:  Phillip Newman Specific rights apply [26] .
              NASA Web Privacy Policy and Important Notices [27]
              A service of: ASD [28]  at NASA [29]  / GSFC [30]
                           & Michigan Tech. U. [31]
----------
Site notes:
  [1] archivepix.html
  [2] image/1810/CTA_inauguratedSarahBrands.jpg
  [3] lib/about_apod.html#srapply
  [4] http://www.uva.nl/en/profile/b/r/s.a.brands/ s.a.brands.html
  [5] http://www.lst1.iac.es/
  [6] https://www.cta-observatory.org/
  [7] https://science.nasa.gov/ems/12_gammarays
  [8] ap160820.html
  [9] https://imagine.gsfc.nasa.gov/science/toolbox... gamma_detectors2.html
  [10] ap120202.html
  [11] ap181017.html
  [12] archivepix.html
  [13] lib/apsubmit2015.html
  [14] lib/aptree.html
  [15] https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apo...
  [16] calendar/allyears.html
  [17] /apod.rss
  [18] lib/edlinks.html
  [19] lib/about_apod.html
  [20] http://asterisk.apod.com/discuss_apod.php?dat...
  [21] ap181019.html
  [22] http://www.phy.mtu.edu/faculty/Nemiroff.html
  [23] http://www.phy.mtu.edu/
  [24] https://antwrp.gsfc.nasa.gov/htmltest/jbonnel...
  [25] http://www.astro.umd.edu/
  [26] lib/about_apod.html#srapply
  [27] https://www.nasa.gov/about/highlights/HP_Priv...
  [28] https://astrophysics.gsfc.nasa.gov/
  [29] https://www.nasa.gov/
  [30] https://www.nasa.gov/centers/goddard/
  [31] http://www.mtu.edu/

--- Mystic BBS v1.12 A39 (Windows/32)
 * Origin: FIDONet - The Positronium Repository (1:393/68)