NGC 6421 (also ESO 393-22) is a magnitude +13.0 star cloud located in the constellation Scorpius.
The star cloud was discovered by British astronomer John Herschel using a 47.5 cm (18.7 inch) f/13 speculum reflecting telescope at the Cape of Good Hope on the 3rd August 1834.
Right Ascension 17h 45m 44.0s, Declination -33° 41' 14"