William Herschel discovered NGC 6642 = H II-205 = h2012 = h3749 on 7 Aug 1784 (sweep 245) and recorded "pB, cL, irregularly E, bM." His position is at the east edge of the globular. From the Cape of Good Hope, JH reported (sweep 793) "globular cluster; pB; R; gpmbM; 2'; resolved into visible, but vS stars 15...16m." His position is good. From Slough (sweep 275), he logged "a beautiful little globular cluster of excessively minute stars, 60" diam; seen in twilight. It must be pB when seen in dark sky."

200/250mm - 8" (6/19/82): fairly bright, small, bright core, fainter halo, no resolution.

400/500mm - 17.5" (5/10/91): fairly bright, fairly small, round, 2' diameter, bright core seems slightly offset. Half a dozen mag 14-15 stars are resolved in the mottled halo. A mag 11 field star 2.2' NW and a mag 13.5 star 1.5' NW of center are collinear with the core. Located in a field rich in faint stars.

600/800mm - 24" (8/23/14): at 375x, this fairly bright gc contains a very bright core and an irregular 2' halo. Stars stream out to the east and west creating an impression of elongation. The core is very lively and a few brighter stars are clearly resolved, though packed together very tightly. Roughly 20 stars are resolved in the halo. At 500x, 30-35 stars are resolved (many popping in/out of view) including 8-10 in a clump at the center and close to the core. A single brighter star is just south of the core and a nice pair (~3" separation) is in the halo on the NNE side. A string of stars extends out of the cluster to the north. Easily visible in the 80mm finder at 25x and the finder field contains M22 just 1.1° SE.

Notes by Steve Gottlieb