William Herschel discovered NGC 4478 = H II-124 = h1298 on 12 Apr 1784 (sweep 189) and described "Two [along with NGC 4476] F, S and one B, L nebula [M 87]. His single position matches NGC 4478. On sweep 245, JH recorded "B; S; R; psbM; 30"; the f of 2 [with NGC 4476]." Kolbold measured the position for both the nucleus and the superimposed star in 1893.

300/350mm - 13.1" (5/14/83): fairly bright, slightly elongated NW-SE, weak concentration.

400/500mm - 17.5" (5/23/87): fairly bright, fairly small, slightly elongated NW-SE, brighter core. Forms a pair with NGC 4476 4.7' WNW. Located 9' WSW of M87.

600/800mm - 24" (5/29/14): bright, fairly small, elongated 5:4 NW-SE, 35"x28", high surface brightness, contains a very small, very bright nucleus. A star is involved on the north side, just 10" N of center. Brighter of a pair with NGC 4476 4.6' WNW. Located 8.7' SW of M87.

Notes by Steve Gottlieb