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.

                               2021 December 1
   [2]The featured image shows the recent partial eclipse of the Moon with
    the eclipsed part appearing red and a blue band due to refraction of
   sunlight through the Earth's atmosphere. Please see the explanation for
                         more detailed information.

                          A Blue-Banded Blood Moon
                          Image Credit: [3]Angel Yu

   Explanation: What causes a blue band to cross the Moon during a lunar
   eclipse? The blue band is real but usually quite hard to see. The
   featured [4]HDR image of last week's lunar eclipse, however -- taken
   from [5]Yancheng, [6]China -- has been digitally processed to equalize
   the Moon's brightness and exaggerate [7]the colors. The [8]gray color
   of the bottom right is [9]the Moon's natural color, directly
   illuminated by sunlight. The upper left part of the Moon is not
   directly lit by the Sun since it is [10]being eclipsed -- it in the
   [11]Earth's shadow. It is faintly lit, though, by sunlight that has
   passed deep through [12]Earth's atmosphere. This part of the Moon is
   red -- and called a [13]blood Moon -- for the same reason that Earth's
   sunsets are red: because air scatters away [14]more blue light than
   red. The unusual [15]blue band is different -- its color is created by
   sunlight that has passed high through Earth's atmosphere, where [16]red
   light is better absorbed by ozone than [17]blue. A [18]total eclipse of
   the Sun will occur tomorrow but, [19]unfortunately, totality be
   [20]visible only near the [21]Earth's South Pole.

                Almost Hyperspace: [22]Random APOD Generator
                Tomorrow's picture: small galaxy, local group
     __________________________________________________________________

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    Authors & editors: [34]Robert Nemiroff ([35]MTU) & [36]Jerry Bonnell
                                 ([37]UMCP)
          NASA Official: Phillip Newman [38]Specific rights apply.
              [39]NASA Web Privacy Policy and Important Notices
                A service of: [40]ASD at [41]NASA / [42]GSFC
                           & [43]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2112/BlueRedMoon_Yu_960.jpg
   3. mailto:%20darkskyangelyu%20@at%20gmail%20.dot%20com
   4. https://en.wikipedia.org/wiki/High_dynamic_range
   5. https://youtu.be/E5d8KY_LU6Q
   6. https://en.wikipedia.org/wiki/China
   7. https://apod.nasa.gov/apod/ap201111.html
   8. https://www.universetoday.com/19626/color-of-the-moon/
   9. https://solarsystem.nasa.gov/moons/earths-moon/in-depth/
  10. https://apod.nasa.gov/apod/ap210525.html
  11. https://apod.nasa.gov/apod/ap211125.html
  12. https://www.nasa.gov/mission_pages/sunearth/science/atmosphere-layers2.html
  13. https://www.timeanddate.com/eclipse/blood-moon.html
  14. https://spaceplace.nasa.gov/blue-sky/en/
  15. https://science.nasa.gov/science-news/science-at-nasa/2014/18sep_lunareclipse
  16. https://www.atoptics.co.uk/highsky/hozon.htm
  17. https://www.pbs.org/newshour/science/ozone-challenge-can-see-turquoise-lunar-eclipse
  18. https://www.nasa.gov/content/dec-4-2021-eclipse
  19. https://static.onecms.io/wp-content/uploads/sites/20/2018/05/21042210_264995290674140_8840525631411191808_n.jpg
  20. https://apod.nasa.gov/apod/ap170730.html
  21. https://en.wikipedia.org/wiki/Antarctica
  22. https://apod.nasa.gov/apod/random_apod.html
  23. https://apod.nasa.gov/apod/ap211130.html
  24. https://apod.nasa.gov/apod/archivepix.html
  25. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  26. https://apod.nasa.gov/apod/lib/aptree.html
  27. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  28. https://apod.nasa.gov/apod/calendar/allyears.html
  29. https://apod.nasa.gov/apod.rss
  30. https://apod.nasa.gov/apod/lib/edlinks.html
  31. https://apod.nasa.gov/apod/lib/about_apod.html
  32. http://asterisk.apod.com/discuss_apod.php?date=211201
  33. https://apod.nasa.gov/apod/ap211202.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. https://apod.nasa.gov/apod/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/