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 18
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                           Comet C/2025 R2 (SWAN)
              Image Credit & [3]Copyright: [4]Team Ciel Austral

   Explanation: [5]A new visitor from the outer [6]Solar System, comet
   [7]C/2025 R2 (SWAN) also known as SWAN25B was only discovered late last
   week, on September 11. That's just day before the comet reached
   perihelion, its closest approach to the Sun. [8]First spotted by
   Vladimir Bezugly in images from the SWAN instrument on the
   [9]sun-staring SOHO spacecraft, the comet was surprisingly bright but
   understandably difficult to see against the Sun's glare. Still close to
   the Sun on the sky, the greenish [10]coma and tail of C/2025 R2 (SWAN)
   are captured in [11]this telescopic snapshot from September 17. Spica,
   alpha star of the constellation Virgo, shines just beyond the upper
   left edge of the frame while the comet is about 6.5 light-minutes from
   planet Earth. Near the western horizon after sunset and slightly
   [12]easier to see in binoculars from the southern hemisphere, this
   comet SWAN will pass near [13]Zubenelgenubi, alpha star of Libra, on
   October 2. [14]C/2025 R2 (SWAN) is scheduled to make its closest
   approach to our fair planet around October 20.

                    Tomorrow's picture: it's complicated
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    Authors & editors: [26]Robert Nemiroff ([27]MTU) & [28]Jerry Bonnell
                                 ([29]UMCP)
          NASA Official: Amber Straughn [30]Specific rights apply.
            [31]NASA Web Privacy, [32]Accessibility, [33]Notices;
                A service of: [34]ASD at [35]NASA / [36]GSFC,
                         [37]NASA Science Activation
                           & [38]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2509/C2025R2_2000.jpg
   3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
   4. https://www.cielaustral.com/
   5. https://apod.nasa.gov/apod/ap250916.html
   6. https://science.nasa.gov/solar-system/
   7. https://earthsky.org/space/new-comet-swan25b-2025/
   8. https://en.wikipedia.org/wiki/C/2025_R2_(SWAN)#Observational_history
   9. https://science.nasa.gov/mission/soho/
  10. https://spaceplace.nasa.gov/comets/en/
  11. https://app.astrobin.com/i/i5qsgj
  12. https://cobs.si/obs_list?id=2659
  13. https://apod.nasa.gov/apod/ap040514.html
  14. https://theskylive.com/c2025r2-info
  15. https://apod.nasa.gov/apod/ap250917.html
  16. https://apod.nasa.gov/apod/archivepix.html
  17. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  18. https://apod.nasa.gov/apod/lib/aptree.html
  19. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  20. https://apod.nasa.gov/apod/calendar/allyears.html
  21. https://apod.com/feed.rss
  22. https://apod.nasa.gov/apod/lib/edlinks.html
  23. https://apod.nasa.gov/apod/lib/about_apod.html
  24. https://asterisk.apod.com/discuss_apod.php?date=250918
  25. https://apod.nasa.gov/apod/ap250919.html
  26. http://www.phy.mtu.edu/faculty/Nemiroff.html
  27. http://www.phy.mtu.edu/
  28. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  29. http://www.astro.umd.edu/
  30. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  31. https://www.nasa.gov/about/highlights/HP_Privacy.html
  32. https://www.nasa.gov/general/accessibility/
  33. https://www.nasa.gov/privacy/
  34. https://astrophysics.gsfc.nasa.gov/
  35. https://www.nasa.gov/
  36. https://www.nasa.gov/centers/goddard/
  37. https://science.nasa.gov/learners
  38. http://www.mtu.edu/