Astronomy Picture of the Day

   [1]Discover the cosmos! Each day a different image or photograph of our
      fascinating universe is featured, along with a brief explanation
                    written by a professional astronomer.

                              2020 December 11
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

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

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

          Tomorrow's picture: wandering toward a Great Conjunction
     __________________________________________________________________

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    Authors & editors: [23]Robert Nemiroff ([24]MTU) & [25]Jerry Bonnell
                                 ([26]UMCP)
          NASA Official: Phillip Newman [27]Specific rights apply.
              [28]NASA Web Privacy Policy and Important Notices
                A service of: [29]ASD at [30]NASA / [31]GSFC
                           & [32]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2012/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. https://www.nasa.gov/content/explore-the-night-sky-hubble-s-messier-catalog-bio
   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. https://apod.nasa.gov/apod/ap201210.html
  13. https://apod.nasa.gov/apod/archivepix.html
  14. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  15. https://apod.nasa.gov/apod/lib/aptree.html
  16. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  17. https://apod.nasa.gov/apod/calendar/allyears.html
  18. https://apod.nasa.gov/apod.rss
  19. https://apod.nasa.gov/apod/lib/edlinks.html
  20. https://apod.nasa.gov/apod/lib/about_apod.html
  21. http://asterisk.apod.com/discuss_apod.php?date=201211
  22. https://apod.nasa.gov/apod/ap201212.html
  23. http://www.phy.mtu.edu/faculty/Nemiroff.html
  24. http://www.phy.mtu.edu/
  25. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  26. http://www.astro.umd.edu/
  27. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  28. https://www.nasa.gov/about/highlights/HP_Privacy.html
  29. https://astrophysics.gsfc.nasa.gov/
  30. https://www.nasa.gov/
  31. https://www.nasa.gov/centers/goddard/
  32. http://www.mtu.edu/