James Dunlop discovered NGC 6204 = D 442 = h3644 on 13 May 1826 and recorded "seven or eight small stars in a group, about 1' diameter, with a minute line of stars on the north side." His position is 15' too far northeast, typical of his rough positions.

John Herschel first recorded NGC 6204 on 1 Jul 1834 as a "cluster moderately compressed class VIII; stars 11.12th mag; S.f. is a brilliant knot of stars, one of which is 8th mag, and the others 9th magnitude." On a later sweep he noted a "singular shaped cluster, irregularly round, compressed VII class, set as it were in a nearly rectangular frame of stars detached from cluster." He included a sketch of the unusual star chains in Plate V, figure 6 and the "brilliant knot of stars" south following is Hogg 22.

200/250mm - 8" (7/13/91 - Southern Baja): about 40 stars in 8' diameter at 63x. Rich appearance over an unresolved haze. A close triple star is in the center with four bright mag 8-9 stars in a tight group off the SE edge (this is a separate cluster Hogg 22).

8" (7/16/82): only a few faint stars are visible over unresolved haze but appears to be rich. This is one of the southernmost clusters I've viewed from Northern California latitude.

400/500mm - 18" (7/9/02 - Magellan Observatory, Australia): at 171x, this is a bright cluster with roughly 80 stars in a 7' circle. Near the center is knot of four stars with additional very faint stars huddled around at 228x. Many of the stars in the cluster are arranged in a few loops and chains. Most of the brighter stars in the cluster are situated around the edges including a line of four stars at the east edge. Four bright stars are off the SE side including mag 7.3 SAO 227189 (catalogued as Hogg 22).

Notes by Steve Gottlieb