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

                         The Helix Nebula from CFHT
     Image Credit & Copyright: [3]CFHT, [4]Coelum, [5]MegaCam, [6]J.-C.
             Cuillandre ([7]CFHT) & [8]G. A. Anselmi ([9]Coelum)

   Explanation: Will our Sun look like this one day? The [10]Helix Nebula
   is one of brightest and closest examples of a [11]planetary nebula, a
   gas [12]cloud created at the end of the life of a Sun-like star. The
   outer gasses of the star [13]expelled into space appear from our
   vantage point as if we are looking down a [14]helix. The remnant
   central stellar core, destined to become a [15]white dwarf star, glows
   in light so [16]energetic it causes the previously expelled gas to
   [17]fluoresce. The [18]Helix Nebula, given a technical designation of
   [19]NGC 7293, lies about 700 [20]light-years away towards the
   [21]constellation of the Water Bearer ([22]Aquarius) and spans about
   2.5 light-years. The [23]featured picture was taken with the
   [24]Canada-France-Hawaii Telescope (CFHT) located atop a dormant
   volcano in [25]Hawaii, [26]USA. A [27]close-up of the [28]inner edge of
   the [29]Helix Nebula shows complex gas knots of [30]unknown origin.

                   Tomorrow's picture: andromedian horizon
     __________________________________________________________________

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    Authors & editors: [42]Robert Nemiroff ([43]MTU) & [44]Jerry Bonnell
                                 ([45]UMCP)
          NASA Official: Phillip Newman [46]Specific rights apply.
              [47]NASA Web Privacy Policy and Important Notices
                A service of: [48]ASD at [49]NASA / [50]GSFC
                           & [51]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2011/Helix2_CFHT_1917.jpg
   3. http://www.cfht.hawaii.edu/
   4. http://www.coelum.com/
   5. http://www.cfht.hawaii.edu/Instruments/Imaging/Megacam/
   6. http://www.cfht.hawaii.edu/~jcc/
   7. http://www.cfht.hawaii.edu/
   8. http://www.coelum.com/coelum/autori/giovanni-anselmi
   9. http://www.coelum.com/
  10. https://en.wikipedia.org/wiki/Helix_Nebula
  11. https://en.wikipedia.org/wiki/Planetary_nebula
  12. https://www.youtube.com/watch?v=KXNSYo8ZdoU
  13. https://apod.nasa.gov/apod/ap171231.html
  14. http://mathworld.wolfram.com/Helix.html
  15. https://imagine.gsfc.nasa.gov/science/objects/dwarfs2.html
  16. https://science.nasa.gov/ems/10_ultravioletwaves
  17. https://www.youtube.com/watch?v=YvN8zFhWn04
  18. http://www.messier.seds.org/xtra/ngc/n7293.html
  19. https://apod.nasa.gov/apod/ap041229.html
  20. https://chandra.harvard.edu/photo/cosmic_distance.html
  21. https://starchild.gsfc.nasa.gov/docs/StarChild/questions/question9.html
  22. https://en.wikipedia.org/wiki/Aquarius_(constellation)
  23. http://www.cfht.hawaii.edu/HawaiianStarlight/AIOM/English/CFHT-Coelum-AIOM-Mar2017.html
  24. https://www.cfht.hawaii.edu/en/about/
  25. https://en.wikipedia.org/wiki/Hawaii#/media/File:Hawaii_in_United_States_(zoom)_(US50)_(-grid).svg
  26. https://www.cia.gov/library/publications/the-world-factbook/geos/us.html
  27. https://www.youtube.com/watch?v=UwAKNMC2PeM
  28. https://apod.nasa.gov/apod/ap080413.html
  29. http://hubblesite.org/newscenter/archive/2003/11/fastfacts
  30. https://ui.adsabs.harvard.edu/abs/2002ApJ...573L..55H/abstract
  31. https://apod.nasa.gov/apod/ap201123.html
  32. https://apod.nasa.gov/apod/archivepix.html
  33. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  34. https://apod.nasa.gov/apod/lib/aptree.html
  35. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  36. https://apod.nasa.gov/apod/calendar/allyears.html
  37. https://apod.nasa.gov/apod.rss
  38. https://apod.nasa.gov/apod/lib/edlinks.html
  39. https://apod.nasa.gov/apod/lib/about_apod.html
  40. http://asterisk.apod.com/discuss_apod.php?date=201124
  41. https://apod.nasa.gov/apod/ap201125.html
  42. http://www.phy.mtu.edu/faculty/Nemiroff.html
  43. http://www.phy.mtu.edu/
  44. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  45. http://www.astro.umd.edu/
  46. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  47. https://www.nasa.gov/about/highlights/HP_Privacy.html
  48. https://astrophysics.gsfc.nasa.gov/
  49. https://www.nasa.gov/
  50. https://www.nasa.gov/centers/goddard/
  51. http://www.mtu.edu/