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/