         APOD: 2018 February 4 - Venus and the Triply Ultraviolet Sun

                         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 February 4
                                      [2]
                    Venus and the Triply Ultraviolet Sun
    Image Credit: NASA [3] / SDO [4] & the AIA, EVE, and HMI teams; Digital
                        Composition: Peter L. Dove [5]

Explanation: An unusual type of solar eclipse occurred in 2012. Usually it is
the Earth's Moon [6]  that eclipses [7]  the Sun. That year, most unusually,
the planet Venus [8]  took a turn. Like a solar eclipse [9]  by the Moon, the
phase of Venus [10]  became a continually thinner crescent [11]  as Venus
became increasingly better aligned with the Sun. Eventually the alignment
became perfect and the phase [12]  of Venus dropped to zero. The dark spot
[13]  of Venus crossed our parent star. The situation could technically be
labeled a Venusian annular eclipse [14]  with an extraordinarily large ring of
fire [15] . Pictured here [16]  during the occultation, the Sun was imaged in
three colors of ultraviolet light by the Earth-orbiting Solar Dynamics
Observatory [17] , with the dark region toward the right corresponding to a
coronal hole [18] . Hours later, as Venus continued in its orbit, a slight
crescent phase [19]  appeared again. The next Venusian transit across the Sun
[20]  will occur in 2117 [21] .

                 Tomorrow's picture: bubble versus cloud [22]

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    Authors & editors: Robert Nemiroff [34] (MTU [35] ) & Jerry Bonnell [36]
                                  (UMCP [37] )
          NASA Official:  Phillip Newman Specific rights apply [38] .
              NASA Web Privacy Policy and Important Notices [39]
              A service of: ASD [40]  at NASA [41]  / GSFC [42]
                           & Michigan Tech. U. [43]
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Site notes:
  [1] archivepix.html
  [2] image/1802/SunVenusUv3_SdoDove_800.jpg
  [3] https://www.nasa.gov/
  [4] https://sdo.gsfc.nasa.gov/
  [5] http://www.flickr.com/photos/pldove/
  [6] http://en.wikipedia.org/wiki/Moon
  [7] http://xjubier.free.fr/en/site_pages/SolarEclipsesGoogleMaps.html
  [8] http://solarsystem.nasa.gov/planets/profile.cfm?Object=Venus
  [9] ap121117.html
  [10]
http://astrosun2.astro.cornell.edu/academics/courses/astro201/venus_phase.htm
  [11] ap010619.html
  [12] ap030810.html
  [13] ap120611.html
  [14] http://www.mreclipse.com/Special/SEprimer.html
  [15] ap020610.html
  [16] http://www.flickr.com/photos/pldove/7344307970/in/photostream/
  [17] http://sdo.gsfc.nasa.gov/
  [18] ap100828.html
  [19] ap130814.html
  [20] http://en.wikipedia.org/wiki/Transit_of_Venus#Past_and_future_transits
  [21] https://en.wikipedia.org/wiki/22nd_century#Transits_and_occultations
  [22] ap180205.html
  [23] ap180203.html
  [24] archivepix.html
  [25] lib/apsubmit2015.html
  [26] lib/aptree.html
  [27] https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  [28] calendar/allyears.html
  [29] /apod.rss
  [30] lib/edlinks.html
  [31] lib/about_apod.html
  [32] http://asterisk.apod.com/discuss_apod.php?date=180204
  [33] ap180205.html
  [34] http://www.phy.mtu.edu/faculty/Nemiroff.html
  [35] http://www.phy.mtu.edu/
  [36] https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  [37] http://www.astro.umd.edu/
  [38] lib/about_apod.html#srapply
  [39] https://www.nasa.gov/about/highlights/HP_Privacy.html
  [40] https://astrophysics.gsfc.nasa.gov/
  [41] https://www.nasa.gov/
  [42] https://www.nasa.gov/centers/goddard/
  [43] http://www.mtu.edu/
