Messier 9 (also M9, NGC 6333, HD 156587 and GCL 60) is a magnitude +8.42 globular star cluster located 25,800 light-years away in the constellation Ophiuchus. M9 can be observed as a faint, small, round spot using 10x50 binoculars in good condition. A 4-inch telescope reveals the central part of the cluster with a diameter of about 3'. Instruments of 6-inch allow you to resolve the brightest stars of the cluster. Messier 9 is positioned close-by to two globular clusters: NGC 6356, about 1° 40' northeast of the cluster; and NGC 6342, located about 1° 40' towards the south-east. The dark nebula Barnard 259 lies in the south-eastern part of M9, and Barnard 64 is located about 25' towards the west.
The cluster was discovered by French astronomer Charles Messier on the 28th May 1764.
Right Ascension 17h 19m 11.78s, Declination -18° 30' 58.5"
The NASA/ESA Hubble Space Telescope has produced the most detailed image so far of Messier 9, a globular star cluster located close to the centre of the galaxy. This ball of stars is too faint to see with the naked eye, yet Hubble can see over 250 000 individual stars shining in it. Messier 9, pictured here, is a globular cluster, a roughly spherical swarm of stars that lies around 25 000 light-years from Earth, near the centre of the Milky Way, so close that the gravitational forces from the galactic centre pull it slightly out of shape. Globular clusters are thought to harbour some of the oldest stars in our galaxy, born when the Universe was just a small fraction of its current age. As well as being far older than the Sun - around twice its age - the stars of Messier 9 also have a markedly different composition, and are enriched with far fewer heavier elements than the Sun.
