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.

                              2025 December 19
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                     Long Shadows of the Montes Caucasus
                   Image Credit & [3]Copyright: Guy Bardon

   Explanation: [4]When the Moon is at its first quarter phase, the Sun
   rises along the [5]Montes Caucasus as seen from the lunar surface. The
   lunar mountain range casts the magnificent, spire-like shadows in this
   telescopic view from planet Earth, looking along the lunar terminator
   or the boundary between lunar night and day. Named for Earth's own
   Caucasus Mountains, the rugged lunar [6]Montes Caucasus peaks, up to 6
   kilometers high, are located between the smooth Mare Imbrium to the
   west and Mare Serenitatis to the east. Still mostly in shadow in this
   first quarter [7]lunarscape, at the left (west) impact craters reflect
   the light of the rising Sun along their outer, eastern crater walls.

                    Tomorrow's picture: the Sun's tattoo
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    Authors & editors: [19]Robert Nemiroff ([20]MTU) & [21]Jerry Bonnell
                                 ([22]UMCP)
          NASA Official: Amber Straughn [23]Specific rights apply.
            [24]NASA Web Privacy, [25]Accessibility, [26]Notices;
                A service of: [27]ASD at [28]NASA / [29]GSFC,
                         [30]NASA Science Activation
                           & [31]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2512/MontesCaucasusCopie.png
   3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
   4. https://science.nasa.gov/moon/moon-phases/
   5. https://en.wikipedia.org/wiki/Montes_Caucasus
   6. https://planetarynames.wr.usgs.gov/Feature/4007
   7. https://www.vaticanobservatory.org/sacred-space-astronomy/caucasus-triangle/
   8. https://apod.nasa.gov/apod/ap251218.html
   9. https://apod.nasa.gov/apod/archivepix.html
  10. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  11. https://apod.nasa.gov/apod/lib/aptree.html
  12. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  13. https://apod.nasa.gov/apod/calendar/allyears.html
  14. https://apod.com/feed.rss
  15. https://apod.nasa.gov/apod/lib/edlinks.html
  16. https://apod.nasa.gov/apod/lib/about_apod.html
  17. https://asterisk.apod.com/discuss_apod.php?date=251219
  18. https://apod.nasa.gov/apod/ap251220.html
  19. http://www.phy.mtu.edu/faculty/Nemiroff.html
  20. http://www.phy.mtu.edu/
  21. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  22. http://www.astro.umd.edu/
  23. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  24. https://www.nasa.gov/about/highlights/HP_Privacy.html
  25. https://www.nasa.gov/general/accessibility/
  26. https://www.nasa.gov/privacy/
  27. https://astrophysics.gsfc.nasa.gov/
  28. https://www.nasa.gov/
  29. https://www.nasa.gov/centers/goddard/
  30. https://science.nasa.gov/learners
  31. http://www.mtu.edu/