              APOD: 2017 December 2 - Messier Craters in Stereo

                         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 December 2
                                      [2]
                          Messier Craters in Stereo
    Image Credit: Apollo 11 [3] , NASA [4] ; Stereo Image Copyright Patrick
                                 Vantuyne [5]

Explanation: Many bright nebulae and star clusters in planet Earth's sky are
associated with the name of astronomer Charles Messier [6] , from his famous
18th century catalog. His name is also given to these two large and remarkable
craters on the Moon. Standouts in the dark [7] , smooth lunar Sea of Fertility
or Mare Fecunditatis, Messier (left) and Messier A have dimensions of 15 by 8
and 16 by 11 kilometers respectively. Their elongated shapes are explained by
a left-to-right moving, extremely shallow-angle trajectory followed by an
impactor that gouged out the craters. The shallow impact also resulted in two
bright rays of material [8] extending along the surface to the right, beyond
the picture. Intended to be viewed with red/blue glasses [9]  (red for the
left eye), this striking stereo picture of the crater pair was recently
created from high resolution scans of two images ( AS11-42-6304 [10] ,
AS11-42-6305 [11] ) taken during the Apollo 11 mission to the moon.

                Tomorrow's picture: super moon silhouettes [12]

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    Authors & editors: Robert Nemiroff [24] (MTU [25] ) & Jerry Bonnell [26]
                                  (UMCP [27] )
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Site notes:
  [1] archivepix.html
  [2] image/1712/MessierCrater3d_vantuyne.jpg
  [3] http://nssdc.gsfc.nasa.gov/planetary/lunar/ apollo11info.html
  [4] http://www.nasa.gov/
  [5] https://www.hq.nasa.gov/alsj/ApAnPaVa.html
  [6] http://messier.seds.org/xtra/history/m-cat.html
  [7] http://lroc.sese.asu.edu/posts/383
  [8] http://lunarnetworks.blogspot.com/2012/04/ lroc-rays-of-messier.html
  [9] http://photojournal.jpl.nasa.gov/Help/ VendorList.html#Glasses
  [10] http://www.lpi.usra.edu/resources/apollo/ frame/?AS11-42-6304
  [11] http://www.lpi.usra.edu/resources/apollo/ frame/?AS11-42-6305
  [12] ap171203.html
  [13] ap171201.html
  [14] archivepix.html
  [15] lib/apsubmit2015.html
  [16] lib/aptree.html
  [17] http://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  [18] calendar/allyears.html
  [19] /apod.rss
  [20] lib/edlinks.html
  [21] lib/about_apod.html
  [22] http://asterisk.apod.com/discuss_apod.php?date=171202
  [23] ap171203.html
  [24] http://www.phy.mtu.edu/faculty/Nemiroff.html
  [25] http://www.phy.mtu.edu/
  [26] http://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  [27] http://www.astro.umd.edu/
  [28] lib/about_apod.html#srapply
  [29] http://www.nasa.gov/about/highlights/HP_Privacy.html
  [30] http://astrophysics.gsfc.nasa.gov/
  [31] http://www.nasa.gov/
  [32] http://www.nasa.gov/centers/goddard/
  [33] http://www.mtu.edu/
