Messier 13 or M13, also designated NGC 6205 and sometimes called the Great Globular Cluster in Hercules or the Hercules Globular Cluster, is a globular cluster of several hundred thousand stars in the constellation of Hercules.
About 145 light-years in diameter, M13 is composed of several hundred thousand stars, the brightest of which is a red giant, the variable star V11, also known as V1554 Herculis, with an apparent visual magnitude of 11.95. M13 is 22,200–25,000 light-years away from Earth, and the globular cluster is one of over one hundred that orbit the center of the Milky Way.
![An early photograph of the Hercules cluster M13 with the CPC925 reflector telescope and Nikon D800 camera from Stuvsta in September 2015 M13 Hercules cluster](https://astro.hal1.se/wp-content/uploads/cache/2023/03/m13-calibrated/1117638773.jpg)
M13 Hercules cluster
An early photograph of the Hercules cluster M13 with the CPC925 reflector telescope and Nikon D800 camera from Stuvsta in September 2015
![Photographed with APO107 refractor telescope and Nikon D800 camera in Stuvsta, September 2016.
5*60s exposure. M13 Hercules cluster](https://astro.hal1.se/wp-content/uploads/cache/2023/03/m13_5st_60s_guidat_lrgb_cropped/3453745993.jpg)
M13 Hercules cluster
Photographed with APO107 refractor telescope and Nikon D800 camera in Stuvsta, September 2016.
5*60s exposure.
![Photographed with APO107 refractor telescope and Atik 360EX CCD monochrome CCD camera from Stuvsta in September 2019.
20min each LRGB filter M13 Hercules cluster](https://astro.hal1.se/wp-content/uploads/cache/2023/03/m13_20min_lrgb_ps2/632186872.jpg)
M13 Hercules cluster
Photographed with APO107 refractor telescope and Atik 360EX CCD monochrome CCD camera from Stuvsta in September 2019.
20min each LRGB filter