Messier 13 (M13), also designated NGC 6205 and sometimes called the Great Globular Cluster in Hercules or the Hercules Globular Cluster, is a globular cluster of about 300,000 stars in the constellation of Hercules.
M13 is about 145 light-years in diameter, and it is composed of several hundred thousand stars, the brightest of which is ared giant, the variable star V11, with an apparent visual magnitude of 11.95. M13 is 25,100 light-years away from Earth.
The Arecibo message of 1974, which contained encoded information about the human race, DNA, atomic numbers, Earth's position and other information, was beamed from the Arecibo Observatory radio telescope towards M13 as an experiment in contacting potential extraterrestrial civilizations in the cluster. However, the experimenters intentionally sabotaged their goal: the message will reach the cluster's past position in 25,000 years. By then, the cluster will occupy a different position in space; it will never receive the message.
The name Hercules is from a Latin translation of Greek Herakles. Herakles' name is translated 'the glory of Hera' or 'the fame of Hera', the prefix of his name relates to Hera, wife of Zeus, the suffix is from Greek -kles, related to Latin cluere, variously translated; 'to listen', 'to hear oneself called', 'to be spoken of', 'called upon'. This constellation is said to represent the Roman Hercules, Greek Herakles, who was the greatest of the Greek heroes and famous for his twelve labors. As an infant Hercules strangled two serpents sent by Juno to kill him as he lay asleep in his cradle. It is suggested that the two serpents represent the the Lunar Nodes. He died on a funeral pyre, became a god, and ascended to Mount Olympus to join the other gods. Engonasin is a Greek title for Hercules, with Roman writers translating it Geniculator or Geniculatus; these terms meaning 'the Kneeling Man'.
HGS Session References
Found in HGS Manual on Page 108
Found in HGS Manual on Page 115