NGC 6440

NGC 6440 is a globular cluster in the constellation Sagittarius discovered by William Herschel on 28 May 1786. It has an apparent magnitude of around 10, with a diameter of about 6 arcminutes, and its Shapley–Sawyer Concentration Class is V.[1]

NGC 6440
The globular cluster NGC 6440 imaged by the Hubble Space Telescope
Observation data (J2000 epoch)
Class	V
Constellation	Sagittarius
Right ascension	17h 48m 52.7s[1]
Declination	−20° 21′ 36.9″[1]
Distance	27.7 kly (8.5 kpc)[2]
Apparent magnitude (V)	10.10[2]
Physical characteristics
Radius	3.15' x 3.15'[1]
Metallicity	${\displaystyle {\begin{smallmatrix}\left[{\ce {Fe}}/{\ce {H}}\right]\end{smallmatrix}}}$ = -0.36[3] dex
Other designations	GCl 77, 1FGL J1748.7-2020, MXB 1746-20[2]