John Herschel discovered NGC 3173 = h3235 on 24 Mar 1835 and noted "F; R: gbM; 40"." His position and description matches ESO 500-016.

400/500mm - 18" (4/10/04): fairly faint, moderately large, round. Sharply concentrated with a moderately bright 15" core surrounded by a very faint, low surface brightness halo requiring averted vision. The galaxy is very close preceding mag 10 SAO 178570 (1.3' from center) and 2.4' NNW of mag 10 SAO 178568!

Notes by Steve Gottlieb