William Herschel discovered NGC 3478 = H III-705 = h801 on 5 Feb 1788 (sweep 808) and simply noted "vF". His position was 1.5' too far north (similar offset as NGC 3583, the next discovery in the sweep). On 19 Mar 1828 (sweep 139), John Herschel logged "F; S; R" and measured an accurate position.

400/500mm - 17.5" (4/6/91): faint, fairly small, elongated 2:1 NW-SE, 1.5'x0.75', large brighter middle but no defined nucleus. A pair of mag 11 stars are 3.9' S and 5.5' SSW with a separation of 2.0'.

Notes by Steve Gottlieb