Terzan 1

Terzan 1, also known as ESO 455-23 and Terzan 1966, is a heavily obscured globular cluster located around 20.000 light-years from Earth in the constellation of Scorpius. It is one of about 150 globular clusters discovered by the French astronomer Agop Terzan in the 1960s-70s, belonging to the Milky Way. Terzan 1 is also an X-ray source.

Terzan 1
Terzan 1 image taken with the Wide Field Planetary Camera 2 on board the NASA/ESA Hubble Space Telescope (north is to the right)[1]
Observation data (J2000 epoch)
Constellation	Scorpius[1]
Right ascension	17h 35m 47.8s[2]
Declination	−30° 28′ 11.0″[2]
Physical characteristics
Other designations	ESO 455-23, Cl Haute-Provence 2, Cl VDBH 235, [KPS2012] MWSC 2635, C 1732-304, Cl Terzan 1, GCl 69
See also: Globular cluster, List of globular clusters

Terzan 1 from the Hubble Space Telescope Wide Field Planetary Camera 2 (north is down)

Terzan 1 has the smallest projected distance to the Milky Way’s center among all known globulars: it is only 4,200 light-years from the center but 21,800 light-years from Earth. In 1980, astronomers detected X-ray bursts from a source located in Terzan 1. Several years later, the source X1732-304 was detected within the cluster with NASA’s Spacelab 2 and ESA’s EXOSAT missions.^[3]