Messier 13 by Hubble Space Telescope; 3.3′ view
|Observation data (J2000 epoch)|
|Right ascension||16h 41m 41.44s|
|Declination||+36° 27′ 36.9″|
|Distance||25.1 kly ()|
|Apparent magnitude (V)||+5.8|
|Apparent dimensions (V)||23′|
|Mass||1036 kg (6×105  M)|
|Estimated age||1.4×1010 yr|
|Notable features||one of the best
of the northern
|Other designations||NGC 6205|
Discovery and visibility
It is located at w:right ascension 16h 41.7m and w:declination +36° 28'. With an w:apparent magnitude of 5.8, it is barely visible with the w:naked eye on a very clear night. Its diameter is about 23 arc minutes and it is readily viewable in small telescopes. Nearby is w:NGC 6207, a 12th magnitude edge-on galaxy that lies 28 arc minutes directly north east. A small galaxy, IC 4617, lies halfway between NGC 6207 and M13, north-northeast of the large globular's center.
M13 is about 145 light-years in w:diameter, and it is composed of several hundred thousand w:stars, the brightest of which is the w:variable star V11 with an apparent magnitude of 11.95. M13 is 25,100 light-years away from w:Earth.
The w:Arecibo message of 1974, designed to communicate the existence of human life to hypothetical extraterrestrials, was transmitted toward M13. The reason was that with a higher star density, the chances of a life harboring planet with intelligent life forms, were higher.
- The w:science fiction novellas "w:Sucker Bait" by w:Isaac Asimov and "w:Question and Answer" by w:Poul Anderson take place on Troas, a world within M13.
- In the science fiction series w:Perry Rhodan, M13 is the location of Arkon, the home world of the race of Arkonides.
- In author Dan Simmon's w:Hyperion Cantos the Hercules cluster is where Earth was secretly moved to after it was supposedly destroyed.
- In w:The Sirens of Titan, w:Kurt Vonnegut writes "Every passing hour brings the Solar System forty-three thousand miles closer to Globular Cluster M13 in Hercules -- and still there are some misfits who insist that there is no such thing as progress."
- Messier 13, SEDS Messier pages
- Messier 13, Galactic Globular Clusters Database page
- Messier 13, High-resolution LRGB image based on 2 hrs total exposure
- Messier 13, Image by Waid Observatory
- NightSkyInfo.com - M13, the Hercules Globular Cluster
- Photometric study of the V2 cepheid in M13
- Period, Amplitude and Light Curve of V38 in M13
- Great Globular Cluster in Hercules (Messier 13/NGC 6205)
- M13 images taken by Stargazer-Observatory
- "SIMBAD Astronomical Database". Results for NGC 6205. http://simbad.u-strasbg.fr/Simbad. Retrieved 2006-11-15.
- Leonard, Peter J. T.; Richer, Harvey B.; Fahlman, Gregory G.. "The mass and stellar content of the globular cluster M13". http://adsabs.harvard.edu/abs/1992AJ....104.2104L.
- distance × sin( diameter_angle / 2 ) = 84 ly. radius