Albert Marth discovered NGC 7420 = m 508 on 6 Sep 1863 and noted "vF, S." His position is accurate.

400/500mm - 17.5" (7/17/93): very faint, small, elongated 4:3 WSW-ENE, 0.7'x0.5', faint stellar nucleus or star superimposed. Located between a mag 9.0 SAO 90876 4.6' WNW and a mag 10.5 star 4.1' ESE. Several faint stars that confuses the observation are near south. These include a close mag 14 pair at 9" separation.

Notes by Steve Gottlieb