James Dunlop discovered NGC 6652 = D 607 = h3747 with his 9-inch f/12 speculum reflector on 28 Jun 1826. He described "a rather bright well-defined round nebula, about 12 or 14 arcseconds diameter, following a star of the 6th mag." He claims 2 observations and the published position is 33' too far east. The cluster is located 7' SE of a mag 6.8 star, so his identification seems secure, despite the rather small estimated size and poor position.

John Herschel observed this globular on 4 sweeps. On 31 Jul 1834 he logged "B; pmE in parallel; gmbM, 60" long, 35" broad, all clearly resolved." A few nights later he wrote "pB; S; lE; 90" long, 75" broad, stars 15m." On a third sweep he described "vB; S; 40"; resolved. Among close stars, which give it an elongated appearance, but do not seem to belong to it."

Pietro Baracchi observed the cluster on 5 Oct 1885 with the 48" Melbourne telescope and wrote "cB, small, irregular shaped, roundish, small vmbM to a very bright center. Resolvable - cluster of minute stars - yes, a little elongated south-following."

200/250mm - 8" (7/31/81): moderately bright, small, compact bright core. A mag 13 star is at the SW edge but there was no other resolution.

400/500mm - 17.5" (5/10/91): fairly bright globular cluster, fairly small, slightly elongated E-W, 2.0'x1.5', sharp small bright core with a substellar nucleus embedded. The mottled halo was not resolved except for a mag 13 star 1' WSW of the core near the edge of the halo and a mag 14 star at the east edge. Located 7' SE of mag 6.9 SAO 210344.

Notes by Steve Gottlieb