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 21
   [2]The featured image shows a composite image of the Sun superposed on
    the Milky Way. The image shows the night sky you would see if the Sun
   was very dim. Please see the explanation for more detailed information.

                         Solstice Sun and Milky Way
       Composite Image Credit & [3]Copyright: [4]Stefan Seip ([5]TWAN)

   Explanation: Welcome to December's solstice, first day of winter in the
   north and summer for the southern hemisphere. Astronomical markers of
   the seasons, [6]solstice and equinox dates are based on the Sun's place
   in its annual journey along the [7]ecliptic, through planet Earth's
   sky. At [8]this solstice, the Sun reaches its maximum southern
   [9]declination of -23.5 degrees today at 15:59 [10]UTC, while its
   [11]right ascension coordinate on the [12]celestial sphere is 18 hours.
   That puts the [13]Sun in the [14]constellation Sagittarius in a
   direction near the [15]center of our Milky Way galaxy. In fact, if you
   could see today's [16]Solstice Sun against faint background stars and
   nebulae (that's [17]really hard to do, especially in the daytime ...)
   your view might look something like this composited panorama. To make
   it, images of [18]our fair galaxy were taken under dark [19]Namibian
   night skies, then stitched together in a panoramic view. From a
   snapshot made on [20]2015 December 21, the Sun was digitally overlayed
   as a brilliant star at today's northern winter solstice position, close
   to the center of [21]the Milky Way.

    Discovery + Outreach: [22]Graduate student research position open for
                                    APOD
                        Tomorrow's picture: X launch
     __________________________________________________________________

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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/WinterSolsticeMW_Seip_2980.jpg
   3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
   4. http://www.astromeeting.de/
   5. https://twanight.org/profile/stefan-seip/
   6. https://scijinks.gov/solstice/
   7. https://en.wikipedia.org/wiki/Ecliptic#/media/File:Ecliptic_with_earth_and_sun_animation.gif
   8. http://earthsky.org/astronomy-essentials/everything-you-need-to-know-december-solstice
   9. https://en.wikipedia.org/wiki/Declination
  10. https://en.wikipedia.org/wiki/Coordinated_Universal_Time
  11. https://en.wikipedia.org/wiki/Right_ascension
  12. https://solarsystem.nasa.gov/basics/chapter2-2/#celestial
  13. https://apod.nasa.gov/apod/ap210606.html
  14. https://chandra.harvard.edu/photo/constellations/sagittarius.html
  15. https://apod.nasa.gov/apod/ap190927.html
  16. https://apod.nasa.gov/apod/ap210620.html
  17. https://static1.bigstockphoto.com/6/0/4/large2/406370303.jpg
  18. https://apod.nasa.gov/apod/ap151107.html
  19. https://en.wikipedia.org/wiki/Namibia
  20. https://apod.nasa.gov/apod/ap151221.html
  21. https://www.nasa.gov/jpl/charting-the-milky-way-from-the-inside-out
  22. https://asterisk.apod.com/viewtopic.php?f=28&t=41989
  23. https://apod.nasa.gov/apod/ap211220.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=211221
  33. https://apod.nasa.gov/apod/ap211222.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/