NGC 6528 is a globular cluster in the constellation Sagittarius, and is listed in the New General Catalogue. It has an apparent magnitude of about 11 and a diameter of about 16 arcminutes, and its Shapley-Sawyer Concentration Class is V, containing stars of 16th magnitude and dimmer.[2] Dreyer described it as "pF, cS, R", meaning poor and faint, considerably small and round.
NGC 6528 | |
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Observation data (J2000 epoch) | |
Class | V |
Constellation | Sagittarius |
Right ascension | 18h 04m 49.61s[1] |
Declination | −30° 03′ 20.8″[1] |
Distance | 25.8 kly (7.9 kpc)[1] |
Apparent magnitude (V) | 10.65[1] |
Physical characteristics | |
Radius | 8.3' x 8.3'[2] |
Metallicity | = -0.11[3] dex |
Other designations | GCl 84, ESO 456-48, VDBH 257[1] |
NGC 6528 is located southwest of NGC 6522, another globular cluster. Both are located in Baade's Window, a relatively clear area near the galactic equator.
The globular cluster was discovered in 1784 by the astronomer William Herschel with his 18-inch telescopes.
The NGC 6528 is unusually metal-rich for a globular cluster, and is very similar in composition to NGC 6553, suggesting an origin in a similar environment.[4]