William Herschel discovered NGC 4210 = H III-850 = h1143 on 20 Mar 1790 (sweep 954) and noted "vF, pS." JH recorded (single observation) "Not vF; pL; R; vgbM; 30"." and measured an accurate position.

400/500mm - 17.5" (4/15/93): moderately bright, moderately large, elongated 4:3 NNW-SSE, 1.8'x1.4'. A mag 13.5 star is 1.0' off the WNW edge. Located 11' SE of mag 6.7 SAO 62870. NGC 4221 lies 16' NNE.

Notes by Steve Gottlieb