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.

                              2026 September 20
     [2]The featured image the Sun in many positions above the Callanish
      stones. Please see the explanation for more detailed information.

                     Analemma over the Callanish Stones
               Image Credit & Copyright: [3]Giuseppe Petricca

   Explanation: If you went outside at the same time every day and took a
   picture that included [4]the Sun, how would the Sun's position change?
   A visual answer to that question is an [5]analemma, a composite image
   taken from the same spot at the same time over the course of a year.
   The [6]featured analemma was composed from images taken every few days
   at noon near the village of [7]Callanish in the [8]Outer Hebrides in
   [9]Scotland, [10]UK. In the foreground are the [11]Callanish
   [12]Stones, a stone circle built around 2700 BC during humanity's
   [13]Bronze Age. It is not known if the placement of the [14]Callanish
   Stones has or had astronomical significance. The ultimate causes for
   the [15]figure-8 shape of this and all analemmas are the [16]tilt of
   the Earth axis and the [17]ellipticity of the [18]Earth's orbit around
   the [19]Sun. At the [20]solstices, the Sun will appear at the top or
   bottom of an analemma. The featured image was taken near the December
   solstice and so the Sun appears near the bottom. [21]Equinoxes,
   however, correspond to analemma middle points -- not the
   [22]intersection point. In two days there will be an [23]equinox
   ("equal night"), when day and night are equal over all of planet Earth.
   Many [24]cultures celebrate a change of season at an [25]equinox.

       APOD's main NASA site is [26]moving: From [27]apod.nasa.gov to
                          [28]science.nasa.gov/apod
                       Tomorrow's picture: open space
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    Authors & editors: [40]Robert Nemiroff ([41]MTU) & [42]Jerry Bonnell
                                 ([43]UMCP)
          NASA Official: Amber Straughn [44]Specific rights apply.
            [45]NASA Web Privacy, [46]Accessibility, [47]Notices;
                A service of: [48]ASD at [49]NASA / [50]GSFC,
                         [51]NASA Science Activation
                           & [52]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2609/CallanishAnalemma_Petricca_1280.jpg
   3. https://www.astrobin.com/users/gmrphotographer/
   4. https://science.nasa.gov/sun/
   5. https://en.wikipedia.org/wiki/Analemma
   6. https://gmrphotographer.net/wordpress/2019/01/29/2017-solar-analemma-over-callanish/
   7. https://en.wikipedia.org/wiki/Callanish
   8. https://en.wikipedia.org/wiki/Outer_Hebrides
   9. https://en.wikipedia.org/wiki/Scotland
  10. https://en.wikipedia.org/wiki/United_Kingdom
  11. https://en.wikipedia.org/wiki/Callanish_Stones
  12. https://youtu.be/5mcPHxuVhWk
  13. https://www.history.com/articles/bronze-age
  14. https://www.youtube.com/watch?v=mkbEhp8hJN8
  15. https://apod.nasa.gov/apod/ap160822.html
  16. https://spaceplace.nasa.gov/seasons/en/
  17. https://mathworld.wolfram.com/Ellipse.html
  18. https://science.nasa.gov/wp-content/uploads/2022/09/Equinox_Solstice-Info-Graphic_WTS.jpg
  19. https://apod.nasa.gov/apod/ap250615.html
  20. https://science.nasa.gov/earth/earth-observatory/winter-and-summer-solstice-6125/
  21. https://apod.nasa.gov/apod/ap210922.html
  22. https://unsplash.com/photos/orange-and-brown-tabby-cat-on-pavement-near-body-of-water-0iNLhORjMGM
  23. https://en.wikipedia.org/wiki/Equinox
  24. http://mentalfloss.com/article/59049/autumnal-equinox-traditions
  25. https://apod.nasa.gov/apod/ap240319.html
  26. https://asterisk.apod.com/viewtopic.php?t=45023
  27. https://apod.nasa.gov/
  28. https://science.nasa.gov/apod
  29. https://apod.nasa.gov/apod/ap260919.html
  30. https://apod.nasa.gov/apod/archivepix.html
  31. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  32. https://apod.nasa.gov/apod/lib/aptree.html
  33. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  34. https://apod.nasa.gov/apod/calendar/allyears.html
  35. https://apod.com/feed.rss
  36. https://apod.nasa.gov/apod/lib/edlinks.html
  37. https://apod.nasa.gov/apod/lib/about_apod.html
  38. https://asterisk.apod.com/discuss_apod.php?date=260920
  39. https://apod.nasa.gov/apod/ap260921.html
  40. https://www.mtu.edu/physics/department/faculty/nemiroff/
  41. https://www.mtu.edu/physics/
  42. https://inspirehep.net/authors/1073087
  43. http://www.astro.umd.edu/
  44. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  45. https://www.nasa.gov/about/highlights/HP_Privacy.html
  46. https://www.nasa.gov/general/accessibility/
  47. https://www.nasa.gov/privacy/
  48. https://science.gsfc.nasa.gov/astrophysics/
  49. https://www.nasa.gov/
  50. https://www.nasa.gov/centers/goddard/
  51. https://science.nasa.gov/learn/about-science-activation/
  52. http://www.mtu.edu/