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.

                              2025 September 22
       [2]The planet Saturn is pictured 6 times in a horizonal column,
    labelled by years with 2020 at the top and 2025 at the bottom. As the
     years progress, Saturn's ring appear less prominent. Please see the
                 explanation for more detailed information.

                              Equinox at Saturn
                  Image Credit & Copyright: [3]Imran Sultan

   Explanation: On Saturn, the rings tell you the season. On [4]Earth,
   today marks an equinox, the time when the [5]Earth's equator tilts
   directly toward the Sun. Since [6]Saturn's grand rings orbit along the
   planet's equator, [7]these rings appear most prominent -- from the
   direction of the Sun -- when the spin axis of Saturn points toward the
   [8]Sun. Conversely, when [9]Saturn's spin axis points to the side, an
   equinox occurs, and the edge-on rings are hard to see from not only the
   Sun -- but [10]Earth. In the [11]featured montage, images of Saturn
   between the years of [12]2020 and 2025 have been superposed to show the
   giant planet passing, with this year's equinox, from summer in the
   north to summer in the south. [13]Yesterday, Saturn was coincidently
   about [14]as close as it gets to planet Earth, and so this month the
   [15]ringed giant's orb is relatively bright and [16]visible throughout
   the night.

               Tomorrow's picture: cathedral to massive stars
     __________________________________________________________________

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     __________________________________________________________________

    Authors & editors: [28]Robert Nemiroff ([29]MTU) & [30]Jerry Bonnell
                                 ([31]UMCP)
          NASA Official: Amber Straughn [32]Specific rights apply.
            [33]NASA Web Privacy, [34]Accessibility, [35]Notices;
                A service of: [36]ASD at [37]NASA / [38]GSFC,
                         [39]NASA Science Activation
                           & [40]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2509/Saturn6Years_Sultan_960.jpg
   3. https://www.instagram.com/imran.astro/
   4. https://science.nasa.gov/earth/facts/
   5. https://www.nasa.gov/wp-content/uploads/2015/06/equator_.png
   6. https://apod.nasa.gov/apod/ap180424.html
   7. https://spaceplace.nasa.gov/saturn-rings/en/
   8. https://science.nasa.gov/sun/
   9. https://science.nasa.gov/saturn/
  10. https://apod.nasa.gov/apod/ap220206.html
  11. https://www.instagram.com/p/DOuLq6ADsV4/
  12. https://apod.nasa.gov/apod/ap250429.html
  13. https://earthsky.org/astronomy-essentials/saturn-at-opposition-closest-brightest-best/
  14. https://assets3.thrillist.com/v1/image/3079021/720x960/scale;webp=auto;jpeg_quality=60.jpg
  15. https://apod.nasa.gov/apod/ap200419.html
  16. https://science.nasa.gov/solar-system/whats-up-september-2025-skywatching-tips-from-nasa/
  17. https://apod.nasa.gov/apod/ap250921.html
  18. https://apod.nasa.gov/apod/archivepix.html
  19. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  20. https://apod.nasa.gov/apod/lib/aptree.html
  21. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  22. https://apod.nasa.gov/apod/calendar/allyears.html
  23. https://apod.com/feed.rss
  24. https://apod.nasa.gov/apod/lib/edlinks.html
  25. https://apod.nasa.gov/apod/lib/about_apod.html
  26. https://asterisk.apod.com/discuss_apod.php?date=250922
  27. https://apod.nasa.gov/apod/ap250923.html
  28. http://www.phy.mtu.edu/faculty/Nemiroff.html
  29. http://www.phy.mtu.edu/
  30. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  31. http://www.astro.umd.edu/
  32. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  33. https://www.nasa.gov/about/highlights/HP_Privacy.html
  34. https://www.nasa.gov/general/accessibility/
  35. https://www.nasa.gov/privacy/
  36. https://astrophysics.gsfc.nasa.gov/
  37. https://www.nasa.gov/
  38. https://www.nasa.gov/centers/goddard/
  39. https://science.nasa.gov/learners
  40. http://www.mtu.edu/