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.

                              2023 September 1
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                   The Great Globular Cluster in Hercules
   Image Credit & [3]Copyright: [4]Serge Brunier, Jean-François Bax, David
                             Vernet [5]OCA/C2PU

   Explanation: [6]In 1716, English astronomer [7]Edmond Halley noted,
   "This is but a little Patch, but it shows itself to the naked Eye, when
   the Sky is serene and the Moon absent." [8]Of course, M13 is now less
   modestly recognized as the Great Globular Cluster in Hercules, one of
   the brightest [9]globular star clusters in the northern sky. [10]Sharp
   telescopic views like this one reveal the spectacular cluster's
   [11]hundreds of thousands of stars. At a distance of 25,000
   light-years, the [12]cluster stars crowd into a region 150 light-years
   in diameter. [13]Approaching the cluster core, upwards of 100 stars
   could be contained in a cube just 3 light-years on a side. For
   comparison, the [14]closest star to the Sun is over 4 light-years away.
   The remarkable range of brightness recorded in this image follows stars
   into the dense cluster core.

                   Tomorrow's picture: wisdom in a flower
     __________________________________________________________________

      [15]< | [16]Archive | [17]Submissions | [18]Index | [19]Search |
   [20]Calendar | [21]RSS | [22]Education | [23]About APOD | [24]Discuss |
                                    [25]>
     __________________________________________________________________

    Authors & editors: [26]Robert Nemiroff ([27]MTU) & [28]Jerry Bonnell
                                 ([29]UMCP)
          NASA Official: Phillip Newman [30]Specific rights apply.
              [31]NASA Web Privacy Policy and Important Notices
                A service of: [32]ASD at [33]NASA / [34]GSFC,
                         [35]NASA Science Activation
                           & [36]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2309/M13-totale-en-cours-crop8.jpg
   3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
   4. https://www.astrobin.com/mxfret/C/
   5. https://www.oca.eu/fr/c2pu-accueil
   6. http://messier.seds.org/xtra/similar/halley_pt.html
   7. http://www.bbc.co.uk/history/historic_figures/halley_edmond.shtml
   8. http://messier.seds.org/m/m013.html
   9. http://en.wikipedia.org/wiki/Globular_cluster
  10. https://www.astrobin.com/mxfret/C/
  11. https://skyandtelescope.org/observing/gobs-of-globs-guide-to-16-spring-globular-clusters/
  12. https://hubblesite.org/contents/news-releases/2008/news-2008-40.html
  13. https://apod.nasa.gov/apod/ap031213.html
  14. https://apod.nasa.gov/apod/ap160825.html
  15. https://apod.nasa.gov/apod/ap230831.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.nasa.gov/apod.rss
  22. https://apod.nasa.gov/apod/lib/edlinks.html
  23. https://apod.nasa.gov/apod/lib/about_apod.html
  24. http://asterisk.apod.com/discuss_apod.php?date=230901
  25. https://apod.nasa.gov/apod/ap230902.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://astrophysics.gsfc.nasa.gov/
  33. https://www.nasa.gov/
  34. https://www.nasa.gov/centers/goddard/
  35. https://science.nasa.gov/learners
  36. http://www.mtu.edu/