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 12
   [2]The featured image shows Comet Leonard passing in front of globular
        star cluster M3. Please see the explanation for more detailed
                                information.

                    Comet Leonard Before Star Cluster M3
                  Image Credit & Copyright: [3]Dan Bartlett

   Explanation: Comet Leonard is now visible to the unaided eye -- but
   just barely. Passing nearest to the Earth today, the comet is [4]best
   seen this week soon after sunset, toward the west, low on the horizon.
   Currently [5]best visible in the north, by late December the comet will
   best be seen from south of [6]Earth's equator. The featured image of
   [7]Comet C/2021 A1 (Leonard) was taken a week ago from [8]California,
   [9]USA. The deep exposure [10]shows in great detail the comet's
   [11]green gas [12]coma and developing [13]dust tail. The comet --
   across our inner [14]Solar System and only light-minutes away -- was
   [15]captured passing nearly in front of [16]globular star cluster
   [17]M3. In contrast, [18]M3 is about 35,000 light-years away. In a
   week, Comet Leonard will [19]pass unusually close to Venus, but will
   [20]continue on and be at its closest to the Sun in early January.

                     Tomorrow's picture: meteor mountain
     __________________________________________________________________

      [21]< | [22]Archive | [23]Submissions | [24]Index | [25]Search |
   [26]Calendar | [27]RSS | [28]Education | [29]About APOD | [30]Discuss |
                                    [31]>
     __________________________________________________________________

    Authors & editors: [32]Robert Nemiroff ([33]MTU) & [34]Jerry Bonnell
                                 ([35]UMCP)
          NASA Official: Phillip Newman [36]Specific rights apply.
              [37]NASA Web Privacy Policy and Important Notices
                A service of: [38]ASD at [39]NASA / [40]GSFC
                           & [41]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2112/M3Leonard_Bartlett_3843.jpg
   3. mailto:%20h2ologg%20@at@%20yahoo%20.dot.%20com
   4. https://earthsky.org/astronomy-essentials/comet-leonard-might-become-2021s-brightest-2022/
   5. http://www.aerith.net/comet/catalog/2021A1/mag2.gif
   6. https://www.nasa.gov/sites/default/files/thumbnails/image/equator_.png
   7. https://en.wikipedia.org/wiki/C/2021_A1_(Leonard)
   8. https://en.wikipedia.org/wiki/California
   9. https://en.wikipedia.org/wiki/United_States
  10. https://thumbs.dreamstime.com/b/two-cats-watching-intently-scared-59713174.jpg
  11. https://www.forbes.com/sites/startswithabang/2018/08/09/this-is-why-comets-glow-an-eerie-green-color/
  12. https://spaceplace.nasa.gov/comet-nucleus/en/
  13. https://apod.nasa.gov/apod/ap210308.html
  14. https://solarsystem.nasa.gov/solar-system/our-solar-system/in-depth/
  15. https://vimeo.com/652658994
  16. https://en.wikipedia.org/wiki/Globular_cluster
  17. https://apod.nasa.gov/apod/ap070415.html
  18. https://apod.nasa.gov/apod/ap070609.html
  19. https://en.wikipedia.org/wiki/C/2021_A1_(Leonard)#/media/File:Animation_of_C%EF%BC%8F2021_A1's_orbit_around_Sun_-_2021_close_approach.gif
  20. https://theskylive.com/cometleonard-info
  21. https://apod.nasa.gov/apod/ap211211.html
  22. https://apod.nasa.gov/apod/archivepix.html
  23. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  24. https://apod.nasa.gov/apod/lib/aptree.html
  25. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  26. https://apod.nasa.gov/apod/calendar/allyears.html
  27. https://apod.nasa.gov/apod.rss
  28. https://apod.nasa.gov/apod/lib/edlinks.html
  29. https://apod.nasa.gov/apod/lib/about_apod.html
  30. http://asterisk.apod.com/discuss_apod.php?date=211212
  31. https://apod.nasa.gov/apod/ap211213.html
  32. http://www.phy.mtu.edu/faculty/Nemiroff.html
  33. http://www.phy.mtu.edu/
  34. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  35. http://www.astro.umd.edu/
  36. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  37. https://www.nasa.gov/about/highlights/HP_Privacy.html
  38. https://astrophysics.gsfc.nasa.gov/
  39. https://www.nasa.gov/
  40. https://www.nasa.gov/centers/goddard/
  41. http://www.mtu.edu/