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 16
     [2]A starfield is seen above a horizon and an orange sunset. In the
     starfield, near the horizon, is a comet with a green head and long
       tail. Please see the explanation for more detailed information.

                        New Comet SWAN25B over Mexico
                 Image Credit & Copyright: [3]Daniel Korona

   Explanation: A newly discovered comet is already visible with
   binoculars. The comet, [4]C/2025 R2 (SWAN) and nicknamed SWAN25B, is
   brightening significantly as it emerges from the Sun's direction and
   might soon become visible on your smartphone -- if not [5]your eyes.
   Although the brightnesses of [6]comets are notoriously hard to predict,
   many comets appear brighter as they approach the Earth, with [7]SWAN25B
   reaching only a quarter of the Earth-Sun distance near October 19.
   Nighttime [8]skygazers will also be watching for a [9]SWAN25B-spawned
   meteor shower around October 5 when our Earth passes through the plane
   of the [10]comet's orbit. The unexpectedly [11]bright comet was
   discovered by an amateur astronomer in images of the [12]SWAN
   instrument on [13]NASA's [14]SOHO satellite. The comet is currently
   best observed in southern skies but is slowly moving north. The
   featured image was captured at sunset three days ago just above the
   western horizon in [15]Zacatecas, [16]Mexico.

                   Tomorrow's picture: sagittarius triplet
     __________________________________________________________________

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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/Swan25B_Korona_1267.jpg
   3. mailto: dakoko_minera at live.com.ar
   4. https://en.wikipedia.org/wiki/C/2025_R2_(SWAN)
   5. https://media.istockphoto.com/id/1128004359/photo/close-up-scottish-fold-cat-head-with-shocking-face-and-wide-open-eyes-frighten-or-surprised.jpg?s=612x612&w=0&k=20&c=HglQ8Nf1PslTuI91T-dfhkln-iEbchjqfhGKCWTbaxg=
   6. https://science.nasa.gov/solar-system/comets/
   7. https://earthsky.org/space/new-comet-swan25b-2025/
   8. https://apod.nasa.gov/apod/ap040808.html
   9. https://skyandtelescope.org/astronomy-news/new-comet-swan25-pops-out-from-behind-the-sun/
  10. https://apod.nasa.gov/apod/ap240811.html
  11. https://theskylive.com/articles/2025/09/comet-swan25b-updates
  12. https://soho.nascom.nasa.gov/data/summary/swan/
  13. https://www.nasa.gov/
  14. https://soho.nascom.nasa.gov/about/about.html
  15. https://youtu.be/JiIIAFeW56E
  16. https://en.wikipedia.org/wiki/Mexico
  17. https://apod.nasa.gov/apod/ap250915.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=250916
  27. https://apod.nasa.gov/apod/ap250917.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/