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.

                              2024 September 21
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                         Sunrise Shadows in the Sky
               Image Credit & [3]Copyright: [4]Emili Vilamala

   Explanation: [5]The defining astronomical moment of this September's
   equinox is at 12:44 UTC on September 22, when the Sun crosses the
   celestial equator moving south in its [6]yearly journey through planet
   Earth's sky. That marks the beginning of [7]fall for our fair planet in
   the northern hemisphere and spring in the southern hemisphere, when day
   and night are nearly equal around the globe. Of course, if you
   celebrate the astronomical change of seasons by watching a sunrise you
   can also [8]look for crepuscular rays. Outlined by shadows cast by
   clouds, crepuscular rays can have a dramatic appearance in the twilight
   sky during any sunrise (or sunset). Due to perspective, the parallel
   cloud shadows will seem to point back to the rising Sun [9]and a place
   due east on your horizon on the equinox date. But in this spectacular
   sunrise skyscape captured in early June, the parallel shadows and
   crepuscular rays appear to converge toward an eastern horizon's more
   northerly sunrise. The well-composed photo places the rising Sun just
   behind the bell tower of a church in the town of Vic, province of
   Barcelona, Catalonia, Spain.

                   Tomorrow's picture: Equinox in the City
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    Authors & editors: [21]Robert Nemiroff ([22]MTU) & [23]Jerry Bonnell
                                 ([24]UMCP)
          NASA Official: Phillip Newman [25]Specific rights apply.
              [26]NASA Web Privacy Policy and Important Notices
                A service of: [27]ASD at [28]NASA / [29]GSFC,
                         [30]NASA Science Activation
                           & [31]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2409/RayosCrepusculares.jpg
   3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
   4. https://www.instagram.com/emili_vilamala/
   5. https://earthsky.org/astronomy-essentials/everything-you-need-to-know-september-equinox/
   6. https://apod.nasa.gov/apod/ap220918.html
   7. https://www.timeanddate.com/calendar/autumnal-equinox.html
   8. https://earthobservatory.nasa.gov/images/76261/crepuscular-rays-india
   9. https://apod.nasa.gov/apod/ap160922.html
  10. https://apod.nasa.gov/apod/ap240920.html
  11. https://apod.nasa.gov/apod/archivepix.html
  12. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  13. https://apod.nasa.gov/apod/lib/aptree.html
  14. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  15. https://apod.nasa.gov/apod/calendar/allyears.html
  16. https://apod.nasa.gov/apod.rss
  17. https://apod.nasa.gov/apod/lib/edlinks.html
  18. https://apod.nasa.gov/apod/lib/about_apod.html
  19. http://asterisk.apod.com/discuss_apod.php?date=240921
  20. https://apod.nasa.gov/apod/ap240922.html
  21. http://www.phy.mtu.edu/faculty/Nemiroff.html
  22. http://www.phy.mtu.edu/
  23. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  24. http://www.astro.umd.edu/
  25. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  26. https://www.nasa.gov/about/highlights/HP_Privacy.html
  27. https://astrophysics.gsfc.nasa.gov/
  28. https://www.nasa.gov/
  29. https://www.nasa.gov/centers/goddard/
  30. https://science.nasa.gov/learners
  31. http://www.mtu.edu/