        APOD: 2017 September 24 - How to Identify that Light in the Sky

                         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.

                              2017 September 24
                                      [2]
                    How to Identify that Light in the Sky
        Image Credit & Copyright: HK (The League of Lost Causes [3] )

Explanation: What is that light in the sky? Perhaps one of humanity's more
common questions, an answer may result from a few quick observations. For
example -- is it moving or blinking? If so, and if you live near a city, the
answer [4]  is typically an airplane, since planes are so numerous and so few
stars and satellites [5]  are bright enough to be seen over the din of
artificial city lights [6] . If not, and if you live far from a city, that
bright light is likely a planet such as Venus [7]  or Mars [8]  -- the former
of which is constrained to appear near the horizon just before dawn or after
dusk. Sometimes the low apparent motion of a distant airplane [9]  near the
horizon makes it hard to tell from a bright planet [10] , but even this can
usually be discerned by the plane's motion over a few minutes. Still unsure?
[11] The featured chart [12]  gives a sometimes-humorous but mostly-accurate
assessment. Dedicated sky enthusiasts will likely note -- and are encouraged
to provide [13]  -- polite corrections.

  Chart translations: Spanish [14] , Italian [15] , Polish [16] , Tamil [17] ,
              Kannada [18] , Latvian [19] , and Norwegian [20]
                      Tomorrow's picture: cygnus x [21]

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    Authors & editors: Robert Nemiroff [33] (MTU [34] ) & Jerry Bonnell [35]
                                  (UMCP [36] )
          NASA Official:  Phillip Newman Specific rights apply [37] .
              NASA Web Privacy Policy and Important Notices [38]
              A service of: ASD [39]  at NASA [40]  / GSFC [41]
                           & Michigan Tech. U. [42]
----------
Site notes:
  [1] archivepix.html
  [2] image/1709/astronomy101_hk_750.jpg
  [3] http://www.leagueoflostcauses.com/
  [4] http://star.arm.ac.uk/objects.html
  [5] ap080604.html
  [6] http://www.darksky.org/nightskyconservation
  [7] ap130512.html
  [8] ap140402.html
  [9]
http://www.kadamsphoto.com/nightphotography/
is-that-a-meteor-in-your-photo-or-is-that-piece-of-space-junk-just-happy-to-
see-you/
  [10] http://earthsky.org/space/why-dont-planets-twinkle-as-stars-do
  [11] http://img.youtube.com/vi/9uuqXXT7VYo/hqdefault.jpg
  [12] http://www.leagueoflostcauses.com/blog/2013/08/astronomy-101.html
  [13] http://asterisk.apod.com/discuss_apod.php?date=170924
  [14] http://www.cosmonoticias.org/como-identificar-esa-luz-en-el-cielo/
  [15]
http://lacuriosona.blogspot.it/2014/06/
come-identificare-quella-luce-nel-cielo.html
  [16] http://www.leagueoflostcauses.com/blog/2014/6/astronomy-fans-are-awesome
  [17]
http://teachersofindia.org/ta/article/
%E0%AE%B5%E0%AE%BF%E0%AE%A3%E0%AF%8D%E0%AE%A3%E0%AE%BF%E0%AE%B2%E0%AF%8D-
%E0%AE%95%E0%AE%BE%E0%AE%A3%E0%AE%AA%E0%AF%8D%E0%AE%AA%E0%AE%9F%E0%AF%81%E0%AE%
AE%E0%AF%8D-%E0%AE%92%E0%AE%B3%E0%AE%BF
  [18]
http://teachersofindia.org/kn/article/
%E0%B2%AC%E0%B2%BE%E0%B2%A8%E0%B2%82%E0%B2%97%E0%B2%B3%E0%B2%A6-
%E0%B2%AC%E0%B3%86%E0%B2%B3%E0%B2%95%E0%B3%81%E0%B2%97%E0%B2%B3%E0%B3%81
  [19]
http://www.starspace.lv/lv/index/nasa-dienas-attels/
kas-ta-par-gaisminu-debesis-09062014.html
  [20] http://www.tv2.no/storm/8917736/
  [21] ap170925.html
  [22] ap170923.html
  [23] archivepix.html
  [24] lib/apsubmit2015.html
  [25] lib/aptree.html
  [26] https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  [27] calendar/allyears.html
  [28] /apod.rss
  [29] lib/edlinks.html
  [30] lib/about_apod.html
  [31] http://asterisk.apod.com/discuss_apod.php?date=170924
  [32] ap170925.html
  [33] http://www.phy.mtu.edu/faculty/Nemiroff.html
  [34] http://www.phy.mtu.edu/
  [35] https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  [36] http://www.astro.umd.edu/
  [37] lib/about_apod.html#srapply
  [38] https://www.nasa.gov/about/highlights/HP_Privacy.html
  [39] https://astrophysics.gsfc.nasa.gov/
  [40] https://www.nasa.gov/
  [41] https://www.nasa.gov/centers/goddard/
  [42] http://www.mtu.edu/
