The Great Hercules Globular Cluster is one of the best known of all globulars. Easily visible to the naked eye in a dark sky, it can be seen on a background image of Hercules as a faint star at the top of the ‘keystone’, the four stars that make up the head of the famous strong-man. Containing several hundred thousand stars in a volume of just under 150 light-years, M13 lies about 25,000 light-years from Earth, and thus spans more than half the width of the full moon. An observer near its center would see a dazzling sight of many thousands of bright stars covering the sky. In 1974, the large radio telescope at Arecibo broadcast a message to this cluster for any extraterrestrials that might be found there.

Taken October 2, 2009, with the ST-8 on the C-14 operating at F:6.3   Sky was very bright as the moon was only 2 days from full. Exposure 15 minutes.


Image taken with the ST-8, April 27, 2009, at F:3.5, 30 minutes exposure, using T & A. Unfortunately, the telescope was poorly balanced and the tracking is not very good.


Image taken May 9, 2007, with the 402 camera and the Meade focal reducer. Exposure is 20 30-second snaps, using track and accumulate. Post processing was done with Maxim DL.

Below are some older shots of M13

Images taken August 15, 2001, with the C-14 operating in FASTAR mode.   Exposure is 120 seconds, using track and accumulate.   The upper left frame is the raw image, the upper right one has been processed with Maxim DL to bring out detail in the cluster, and the bottom left is a T&A color grab, also processed with Maxim.  The weather conditions were marginal, with a strong breeze.