¿

                        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 August 24
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                              Crescent Moon HDR
     Image Credit & [3]Copyright: [4]Miguel Claro ([5]TWAN, [6]Dark Sky
                                  Alqueva)

   Explanation: How come the crescent Moon doesn't look like this? For one
   reason, because your eyes can't simultaneously [7]discern bright and
   dark regions like this. Called [8]earthshine or the da Vinci glow, the
   unlit part of a [9]crescent Moon is visible but usually hard to see
   because it is much dimmer than the sunlit arc. In our digital age,
   however, the differences in brightness can be artificially reduced. The
   [10]featured image is actually a digital composite of 15 short
   exposures of the bright crescent, and 14 longer exposures of the dim
   remainder. The origin of the [11]da Vinci glow, as explained by
   [12]Leonardo da Vinci about 510 years ago, is sunlight reflected first
   by the [13]Earth to the Moon, and then back from the [14]Moon to the
   Earth.

                   Tomorrow's picture: around a black hole
     __________________________________________________________________

      [15]< | [16]Archive | [17]Submissions | [18]Index | [19]Search |
   [20]Calendar | [21]RSS | [22]Education | [23]About APOD | [24]Discuss |
                                    [25]>
     __________________________________________________________________

    Authors & editors: [26]Robert Nemiroff ([27]MTU) & [28]Jerry Bonnell
                                 ([29]UMCP)
          NASA Official: Phillip Newman [30]Specific rights apply.
              [31]NASA Web Privacy Policy and Important Notices
                A service of: [32]ASD at [33]NASA / [34]GSFC
                           & [35]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2008/HdrMoon_Claro_2000.jpg
   3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
   4. http://www.miguelclaro.com/wp/
   5. http://www.twanight.org/claro
   6. http://www.darkskyalqueva.com/
   7. https://psychology.stackexchange.com/questions/5408/sensitivity-of-human-eye-to-luminance
   8. https://en.wikipedia.org/wiki/Planetshine
   9. https://solarsystem.nasa.gov/resources/676/phases-of-the-moon/
  10. https://www.miguelclaro.com/wp/portfolio/da-vince-glow-revealed-in-a-high-dynamic-range-of-a-crescent-moon/
  11. https://apod.nasa.gov/apod/ap190504.html
  12. https://en.wikipedia.org/wiki/Leonardo_da_Vinci
  13. https://earthobservatory.nasa.gov/
  14. https://moon.nasa.gov/
  15. https://apod.nasa.gov/apod/ap200823.html
  16. https://apod.nasa.gov/apod/archivepix.html
  17. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  18. https://apod.nasa.gov/apod/lib/aptree.html
  19. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  20. https://apod.nasa.gov/apod/calendar/allyears.html
  21. https://apod.nasa.gov/apod.rss
  22. https://apod.nasa.gov/apod/lib/edlinks.html
  23. https://apod.nasa.gov/apod/lib/about_apod.html
  24. http://asterisk.apod.com/discuss_apod.php?date=200824
  25. https://apod.nasa.gov/apod/ap200825.html
  26. http://www.phy.mtu.edu/faculty/Nemiroff.html
  27. http://www.phy.mtu.edu/
  28. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  29. http://www.astro.umd.edu/
  30. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  31. https://www.nasa.gov/about/highlights/HP_Privacy.html
  32. https://astrophysics.gsfc.nasa.gov/
  33. https://www.nasa.gov/
  34. https://www.nasa.gov/centers/goddard/
  35. http://www.mtu.edu/