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Messier 9 is a dense, spherical collection of hundreds of thousands of stars held together by gravity, located about 25,000 light-years from Earth in the constellation Ophiuchus. It's one of the closest globular clusters to our galaxy's center, making it valuable for astronomers studying the structure and history of the Milky Way.
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Messier 9 or M9 (also designated NGC 6333) is a globular cluster in the constellation of Ophiuchus. It is positioned in the southern part of the constellation to the southwest of Eta Ophiuchi, and lies atop a dark cloud of dust designated Barnard 64. The cluster was discovered by French astronomer Charles Messier on June 3, 1764, who described it as a "nebula without stars". In 1783, English astronomer William Herschel was able to use his reflector to resolve individual stars within the cluster. He estimated the cluster to be 7–8′ in diameter with stars densely packed near the center.
M9 has an apparent magnitude of 7.9, an angular size of 9.3′, and can be viewed with a small telescope. It is one of the nearer globular clusters to the center of the galaxy as is around 5,500 light-years from the Galactic Center. Its distance from Earth is 25,800 light-years.