What is m13?

M13 (also known as the Great Hercules Cluster) is a ball-shaped cluster of stars located in the constellation Hercules, about 25,000 light years away from Earth. It contains over 100,000 stars, with a diameter of about 145 light years. M13 was discovered by Edmond Halley in 1714 and was later catalogued by Charles Messier in 1764. M13 is one of the brightest and largest globular clusters visible from Earth, and it is a popular target for amateur and professional astronomers alike. Its stars are estimated to be around 14 billion years old, making them some of the oldest known stars in our galaxy. M13 also contains several hundred blue straggler stars, which appear to be younger than the other stars in the cluster, possibly formed through stellar collisions or mergers. The Great Hercules Cluster can be observed with the naked eye as a faint fuzzy patch in a dark sky, but it is best viewed through a telescope, where its individual stars can be resolved.