James Dunlop discovered NGC 5999 = D 343 = h3612 on 8 May 1826 and described "a pretty large faint nebula, with several minute stars in it; round figure, 4' or 5' diameter, resolvable." His position was off by ~10' west-southwest. JH made a single observation on 9 Jul 1834 and reported "cluster VI class. A pretty rich large cluster, round; little compressed in the middle, 12', stars 12..14th mag, nearly fills field; middle taken."

400/500mm - 18" (7/7/02 - Magellan Observatory, Australia): at 229x, this is a fairly rich, moderately large cluster. In the center is a striking elliptical ring of roughly two dozen stars. Surrounding this annulus is a larger loop of stars forming a heart-shaped asterism. The looping star patterns make this an interesting visual target! The diameter is roughly 8', though there is no distinct border.

Notes by Steve Gottlieb