Édouard Stephan discovered NGC 6040 = St I-1, along with NGC 6041 and NGC 6042, on 27 Jun 1870. His micrometric position is an exact match with the brighter northern component of this pair (Arp 71). Many sources label the northern component as NGC 6040A with the southern galaxy NGC 6040B. MCG misidentifies this galaxy as IC 1170.

300/350mm - 13.1" (5/14/83): very faint, small, diffuse.

400/500mm - 17.5" (5/13/88): faint, small, elongated 5:2 SSW-NNE, low even surface brightness. Forms a close interacting system with NGC 6040B 26" S. The companion appeared very faint, very small, slightly elongated E-W.

First of three NGC galaxies with NGC 6041 2.7' SE and NGC 6042 4.3' SE. Also, IC 1170 is just visible 2.0' SSE. Located within the central core of AGC 2151.

17.5" (3/23/85): faint, small, elongated SSW-NNE. First of 3. NGC 6040B was not resolved.

600/800mm - 24" (6/4/16): at 322x; fairly faint, fairly small, elongated 5:2 SW-NE, small brighter core. The southwest and northeast extensions are slightly curved or misaligned. NGC 6040B, just 26" S of center, appeared fairly faint, small, round, 12" diameter. Easily visible due to relatively high surface brightness.

Notes by Steve Gottlieb