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.

                              2026 September 21
    [2]A starfield is shown against a patchy red-glowing background. Two
   irregular brown trails occur, the lower of which culminates in a bright
     pink and white region. Please see the explanation for more detailed
                                information.

                          Cocoon Nebula Wide Field
                 Image Credit & Copyright: [3]Piotr Czerski

   Explanation: When does a nebula look like a comet? In this crowded
   starfield covering over two degrees within the high-flying
   [4]constellation of the Swan ([5]Cygnus), the eye is drawn to the
   Cocoon Nebula. A compact star forming region, the [6]cosmic Cocoon
   punctuates a nebula bright in [7]emission and [8]reflection on the
   lower right, with a long trail of interstellar dust clouds to the left,
   making the entire complex appear a bit [9]like a comet. Cataloged as
   [10]IC 5146, the central bright head of the nebula spans about 10
   [11]light years, while the dark [12]dusty tail spans nearly 100 light
   years. Both are located about 2,500 light years away. A bright star
   near the colorful nebula's center likely [13]supplies power and helps
   [14]clear out a cavity. The long dusty filaments of the tail, although
   dark in this [15]visible light image, hide [16]stars in the process of
   [17]formation. The [18]featured image was captured in July from
   [19]Death Valley, [20]California, [21]USA.

       APOD's main NASA site is [22]moving: From [23]apod.nasa.gov to
                          [24]science.nasa.gov/apod
                     Tomorrow's picture: triple eclipse
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    Authors & editors: [36]Robert Nemiroff ([37]MTU) & [38]Jerry Bonnell
                                 ([39]UMCP)
          NASA Official: Amber Straughn [40]Specific rights apply.
            [41]NASA Web Privacy, [42]Accessibility, [43]Notices;
                A service of: [44]ASD at [45]NASA / [46]GSFC,
                         [47]NASA Science Activation
                           & [48]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2609/Cocoon_Czerski_3000.jpg
   3. https://app.astrobin.com/u/PiotrC
   4. https://spaceplace.nasa.gov/constellations/
   5. https://en.wikipedia.org/wiki/Cygnus_(constellation)
   6. https://www.universetoday.com/articles/the-cosmic-cocoon-ic-5146-by-tom-v-davis
   7. https://en.wikipedia.org/wiki/Emission_nebula
   8. https://apod.nasa.gov/apod/ap260407.html
   9. https://apod.nasa.gov/apod/ap211230.html
  10. https://en.wikipedia.org/wiki/IC_5146
  11. https://spaceplace.nasa.gov/light-year/
  12. https://science.nasa.gov/universe/stories/quick-reads/be-glad-you-dont-have-to-dust-in-space/
  13. https://youtu.be/WsOsxbAySGo
  14. https://ui.adsabs.harvard.edu/abs/2002AJ....123..304H/abstract
  15. https://science.nasa.gov/ems/09_visiblelight/
  16. https://science.nasa.gov/universe/stars/
  17. https://apod.nasa.gov/apod/ap250623.html
  18. https://www.instagram.com/p/DbbKvmTjLrv/
  19. https://youtu.be/KPrsxzNBUPM
  20. https://en.wikipedia.org/wiki/California
  21. https://user.iiasa.ac.at/~marek/fbook/04/print/us.html
  22. https://asterisk.apod.com/viewtopic.php?t=45023
  23. https://apod.nasa.gov/
  24. https://science.nasa.gov/apod
  25. https://apod.nasa.gov/apod/ap260920.html
  26. https://apod.nasa.gov/apod/archivepix.html
  27. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  28. https://apod.nasa.gov/apod/lib/aptree.html
  29. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  30. https://apod.nasa.gov/apod/calendar/allyears.html
  31. https://apod.com/feed.rss
  32. https://apod.nasa.gov/apod/lib/edlinks.html
  33. https://apod.nasa.gov/apod/lib/about_apod.html
  34. https://asterisk.apod.com/discuss_apod.php?date=260921
  35. https://apod.nasa.gov/apod/ap260922.html
  36. https://www.mtu.edu/physics/department/faculty/nemiroff/
  37. https://www.mtu.edu/physics/
  38. https://inspirehep.net/authors/1073087
  39. http://www.astro.umd.edu/
  40. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  41. https://www.nasa.gov/about/highlights/HP_Privacy.html
  42. https://www.nasa.gov/general/accessibility/
  43. https://www.nasa.gov/privacy/
  44. https://science.gsfc.nasa.gov/astrophysics/
  45. https://www.nasa.gov/
  46. https://www.nasa.gov/centers/goddard/
  47. https://science.nasa.gov/learn/about-science-activation/
  48. http://www.mtu.edu/