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 30
     [2]A starfield is shown that has a bright comet. The comet shows a
   green head on the lower left and an ion tail with significant structure
    extending out to the upper right. Please see the explanation for more
                            detailed information.

                           Comet Lemmon Brightens
        Image Credit & Copyright: Victor Sabet & [3]Julien De Winter

   Explanation: Comet Lemmon is brightening and moving into morning
   northern skies. Besides [4]Comet SWAN25B and [5]Comet ATLAS, [6]Comet
   C/2025 A6 (Lemmon) is now the third comet currently visible with
   binoculars and on long camera exposures. [7]Comet Lemmon was discovered
   early this year and is still headed into the inner [8]Solar System. The
   comet will round the Sun on November 8, but first it will pass its
   nearest to the Earth -- at about half the [9]Earth-Sun distance -- on
   October 21. Although the brightnesses of comets are [10]notoriously
   hard to predict, optimistic estimates have [11]Comet Lemmon then
   becoming visible to the unaided eye. The [12]comet should be best seen
   in predawn skies until mid-October, when it also becomes visible in
   evening skies. The [13]featured image showing the comet's split and
   rapidly changing ion [14]tail was taken in [15]Texas, [16]USA late last
   week.

                  Growing Gallery: [17]Comet Lemmon in 2025
                       Tomorrow's picture: mopping up
     __________________________________________________________________

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    Authors & editors: [29]Robert Nemiroff ([30]MTU) & [31]Jerry Bonnell
                                 ([32]UMCP)
          NASA Official: Amber Straughn [33]Specific rights apply.
            [34]NASA Web Privacy, [35]Accessibility, [36]Notices;
                A service of: [37]ASD at [38]NASA / [39]GSFC,
                         [40]NASA Science Activation
                           & [41]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2509/CometLemmon_DeWinter_3549.jpg
   3. https://www.instagram.com/dwj85
   4. https://apod.nasa.gov/apod/ap250916.html
   5. https://apod.nasa.gov/apod/ap250929.html
   6. https://en.wikipedia.org/wiki/C/2025_A6_(Lemmon)
   7. https://earthsky.org/space/5-bright-comets-approaching-earth-charts-2025-2026/
   8. https://science.nasa.gov/solar-system/
   9. https://en.wikipedia.org/wiki/Astronomical_unit
  10. https://www.shutterstock.com/image-photo/cat-sitting-front-laptop-stares-600nw-553939873.jpg
  11. https://theskylive.com/c2025a6-info
  12. https://science.nasa.gov/solar-system/comets/facts/
  13. https://app.astrobin.com/i/lsnen5
  14. https://en.wikipedia.org/wiki/Comet_tail
  15. https://en.wikipedia.org/wiki/Texas
  16. https://www.cia.gov/the-world-factbook/countries/united-states/
  17. https://www.facebook.com/media/set/?set=a.791387673589812&type=3
  18. https://apod.nasa.gov/apod/ap250929.html
  19. https://apod.nasa.gov/apod/archivepix.html
  20. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  21. https://apod.nasa.gov/apod/lib/aptree.html
  22. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  23. https://apod.nasa.gov/apod/calendar/allyears.html
  24. https://apod.com/feed.rss
  25. https://apod.nasa.gov/apod/lib/edlinks.html
  26. https://apod.nasa.gov/apod/lib/about_apod.html
  27. https://asterisk.apod.com/discuss_apod.php?date=250930
  28. https://apod.nasa.gov/apod/ap251001.html
  29. http://www.phy.mtu.edu/faculty/Nemiroff.html
  30. http://www.phy.mtu.edu/
  31. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  32. http://www.astro.umd.edu/
  33. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  34. https://www.nasa.gov/about/highlights/HP_Privacy.html
  35. https://www.nasa.gov/general/accessibility/
  36. https://www.nasa.gov/privacy/
  37. https://astrophysics.gsfc.nasa.gov/
  38. https://www.nasa.gov/
  39. https://www.nasa.gov/centers/goddard/
  40. https://science.nasa.gov/learners
  41. http://www.mtu.edu/