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. 2022 August 4 [2]See Explanation. Clicking on the picture will download the highest resolution version available. M13: The Great Globular Cluster in Hercules Image Credit & [3]Copyright: [4]Joan Josep Isach Cogollos Explanation: [5]In 1716, English astronomer [6]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." [7]Of course, M13 is now less modestly recognized as the Great Globular Cluster in Hercules, one of the brightest [8]globular star clusters in the northern sky. [9]Sharp telescopic views like this one reveal the spectacular cluster's [10]hundreds of thousands of stars. At a distance of 25,000 light-years, the [11]cluster stars crowd into a region 150 light-years in diameter. [12]Approaching the cluster core upwards of 100 stars could be contained in a cube just 3 light-years on a side. For comparison, the [13]closest star to the Sun is over 4 light-years away. The remarkable range of brightness [14]recorded in this image follows stars into the dense cluster core. Distant background galaxies in the medium-wide field of view include NGC 6207 at the upper left. Tomorrow's picture: A Beautiful Trifid __________________________________________________________________ [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/2208/M13_final2_sinfirma.jpg 3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 4. https://www.astrobin.com/users/isach/ 5. http://messier.seds.org/xtra/similar/halley_pt.html 6. http://www.bbc.co.uk/history/historic_figures/halley_edmond.shtml 7. http://messier.seds.org/m/m013.html 8. http://en.wikipedia.org/wiki/Globular_cluster 9. https://www.astrobin.com/6h6uzz/ 10. https://skyandtelescope.org/observing/gobs-of-globs-guide-to-16-spring-globular-clusters/ 11. https://hubblesite.org/contents/news-releases/2008/news-2008-40.html 12. https://apod.nasa.gov/apod/ap031213.html 13. https://apod.nasa.gov/apod/ap160825.html 14. https://www.astrobin.com/n9wcu8/0/ 15. https://apod.nasa.gov/apod/ap220803.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=220804 25. https://apod.nasa.gov/apod/ap220805.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/