NGC 6624 | |
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Observation data (J2000 epoch) | |
Constellation | Sagittarius |
Right ascension | 18h 23m 41s |
Declination | −30° 21′ 39″ |
Distance | 25.8 ± 1.1 kly (7.91 ± 0.34 kpc) |
Apparent magnitude (V) | 7.6 |
Apparent dimensions (V) | 8.8 arcminutes[1] |
Physical characteristics | |
Metallicity | = -0.56 ± 0.27[2] dex |
Other designations | ESO 457-11, GCl 93, CD−30 15631, CPD−30 5486, HD 168943[3] |
NGC 6624 is a globular cluster in the constellation Sagittarius. It was discovered on 24 June 1784 by the astronomer William Herschel. It is given an apparent magnitude of 7.6 to 8.5.[4] Six pulsars are known in NGC 6624. The first of these to be discovered was PSR J1823-3021A. This globular cluster also contains 4U 1820-30, a low-mass X-ray binary with an orbital period of only 11.5 minutes.
NGC 6624 is visible as a hazy spot with a small telescope, and appears as a star-like object with binoculars. Its core appears significantly condensed.[1] It is located 0.8 degrees southeast of the star Delta Sagittarii,[5] and is about 1.17 kpc (3.8 kly) from the Galactic Center.[2]