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 25
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                        The Tail of a Christmas Comet
       Image Credit & [3]Copyright: Rolando Ligustri ([4]CARA Project,
                          [5]CAST) and Lukas Demetz

   Explanation: [6]The tail of a comet streams across this three degree
   wide telescopic field of view captured under dark Namibian skies on
   December 21. In outburst only a few days ago and just reaching naked
   eye visibility [7]Comet Leonard (C/2021 A1) is this year's brightest
   comet. Binoculars will make the diffuse comet easier to spot though,
   close to the western horizon after sunset. Details revealed in the
   sharp image show the comet's coma with a greenish tinge, and [8]follow
   the interaction of the comet's [9]ion tail with magnetic fields in the
   solar wind. After passing closest to Earth on December 12 and Venus on
   December 18, Comet Leonard is heading toward perihelion, its closest
   approach to the Sun on January 3rd. [10]Appearing in late December's
   beautiful evening skies after sunset, [11]Comet Leonard has also become
   known as 2021's Christmas Comet.

                Launch Update: [12]James Webb Space Telescope
                       Tomorrow's picture: the icy sky
     __________________________________________________________________

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    Authors & editors: [24]Robert Nemiroff ([25]MTU) & [26]Jerry Bonnell
                                 ([27]UMCP)
          NASA Official: Phillip Newman [28]Specific rights apply.
              [29]NASA Web Privacy Policy and Important Notices
                A service of: [30]ASD at [31]NASA / [32]GSFC
                           & [33]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2112/C2021A1_211221.jpg
   3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
   4. http://cara.uai.it/
   5. http://www.castfvg.it/
   6. https://solarsystem.nasa.gov/asteroids-comets-and-meteors/comets/overview/
   7. https://earthsky.org/astronomy-essentials/comet-leonard-might-become-2021s-brightest-2022/
   8. https://stereo.gsfc.nasa.gov/news/cometleonard.shtml
   9. https://astronomy.swin.edu.au/cosmos/c/Cometary+Gas+Tail
  10. https://apod.nasa.gov/apod/ap211223.html
  11. https://www.planetary.org/articles/how-to-see-comet-leonard
  12. https://blogs.nasa.gov/webb/2021/12/23/join-us-to-watch-the-webb-launch-live/
  13. https://apod.nasa.gov/apod/ap211224.html
  14. https://apod.nasa.gov/apod/archivepix.html
  15. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  16. https://apod.nasa.gov/apod/lib/aptree.html
  17. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  18. https://apod.nasa.gov/apod/calendar/allyears.html
  19. https://apod.nasa.gov/apod.rss
  20. https://apod.nasa.gov/apod/lib/edlinks.html
  21. https://apod.nasa.gov/apod/lib/about_apod.html
  22. http://asterisk.apod.com/discuss_apod.php?date=211225
  23. https://apod.nasa.gov/apod/ap211226.html
  24. http://www.phy.mtu.edu/faculty/Nemiroff.html
  25. http://www.phy.mtu.edu/
  26. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  27. http://www.astro.umd.edu/
  28. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  29. https://www.nasa.gov/about/highlights/HP_Privacy.html
  30. https://astrophysics.gsfc.nasa.gov/
  31. https://www.nasa.gov/
  32. https://www.nasa.gov/centers/goddard/
  33. http://www.mtu.edu/