William Herschel discovered NGC 470 = H III-250, along with NGC 474, on 13 Dec 1784 (sweep 338) and logged both as "Two. vF, vS, R, almost stellar 4' or 5' from each other, nearly in a parallel." On 8 Oct 1785 (sweep 462) he noted "pB, L, R, mbM." and on 3 Dec 1787 (sweep 788) he noted "pB, cL, R, gbM, the preceding of two."

200/250mm - 8" (10/13/81): faint, small, round.

300/350mm - 13.1" (8/24/84): fairly faint, moderately large, diffuse, elongated 3:2 NNW-SSE, weak concentration at center. Largest of three with NGC 467 11' SW and NGC 474 6' E.

600/800mm - 24" (1/12/13): very bright, fairly large, elongated 2:1 NW-SE, 1.8'x0.9', high surface brightness. The halo gradually and weakly increases towards the center and then a sharp increase to a bright, quasi-stellar nucleus. Forms a 5.5' pair with NGC 474 to the east. NGC 467 lies 11' SW.

900/1200mm - 48" (10/25/14): very bright, large, elongated 3:2 NNW-SSE, ~1.8'x1.2'. The bright core contains an intense circular nucleus. Two spiral arms are visible with the brighter and better defined arm on the southwest side of the core. It extends ~40" SW-NE and is fairly narrow and straight. A second matching arm to the northeast of the core also stretches SW-NE, but has a lower contrast. Neither arm clearly connects to the nucleus, so they appear more as bright arcs.

Notes by Steve Gottlieb