NGC 6205, also known as the Great globular cluster in Hercules, is one of the best known globulars of the Northern celestial hemisphere. The globular contains hundreds of thousands of stars, contained within a volume about 145 light years across. In 1974 the radio telescope of the Arecibo Observatory sent NGC 6205 a message as part of the search for extraterrestrial intelligence. Due to the globular's distance, a reply may be received on Earth in 50,000 years time.