William Herschel discovered NGC 5321 = H III-423 = h1680 on 2 May 1785 (sweep 406) and recorded "Two, eF, stellar, the time and number taken between them. The northern one is the faintest; distance about 4 or 5' not far from the meridian." His single position is 2' southwest of NGC 5321 = CGCG 190-065 and his description is an excellent fit with NGC 5318 and NGC 5321, which are separated by 4.6' in position angle 160° (NNW-SSE). The only discrepancy is the northern object NGC 5318) is brighter.

JH made two observations (one good position), calling it "eF; at first sight like a *, but on long attention a pL neb surrounds it" on sweep 337 and "pB; R; smbM." on sweep 74. But he assumed this object was new and his father's III-422 applied to NGC 5312 = h1676. As a result, JH is credited with the discovery of NGC 5321 in the GC and NGC. But NGC 5312 is over 10' southwest of NGC 5318 and the orientation doesn't match WH's description ("not far from the meridian"). Reassigning the historical designations based on this analysis, results in h1676 = GC 3664 = NGC 5312, III-422 = h1679 = GC 3668 = NGC 5318 and III-423 = h1680 = GC 3670 = NGC 5321.

400/500mm - 17.5" (5/22/93): faint, very small, round. Two faint mag 14.5-15 stars are close west [mag 14.5 1.2' WSW] and two mag 11 stars are 3.6' W and 3.8' SW. NGC 5318 lies 4' NNW and NGC 5312 11' W.

900/1200mm - 48" (4/15/10): at 510x appeared bright, fairly large, elongated 2:1 SW-NE, ~0.5'x0.25'. Contains a small, bright nucleus. Located 4.6' SSE of NGC 5318. Forms the vertex of an isosceles triangle with two mag 11 stars ~3.7' WNW and SW. A mag 14.5 star lies 1.2' WSW of center.

Notes by Steve Gottlieb