John Herschel discovered NGC 5135 = h3502 on 8 May 1834 and logged "pB; S; E." His position is accurate.
300/350mm - 13.1" (5/26/84): fairly faint, small, elongated WNW-ESE, fairly bright stellar nucleus. The NGC 5150/NGC 5153 pair lies 30' NE. This is a Seyfert 2 galaxy with an active starburst nucleus.
Notes by Steve Gottlieb