Albert Marth discovered NGC 6408 = m 340 = St II-15 on 2 Jun 1864 and noted "F, S, R, gbM." His position is 1' too far north. Édouard Stephan independently rediscovered the galaxy on 16 Jul 1871. His micrometric position is very accurate.

400/500mm - 17.5" (8/1/89): fairly faint, fairly small, slightly elongated ~E-W, weak concentration, fairly low surface brightness. Located in a rich star field between a mag 13.5 star 1.8' W and a mag 14 star 1.1' SE.

Notes by Steve Gottlieb