John Herschel discovered NGC 5166 = h1608 on 29 Apr 1827 and logged "pF; R; bM; 30"." His mean position from 3 observations matches UGC 8463.

400/500mm - 17.5" (5/15/99): pretty edge-on 5:1 oriented WSW-ENE, 1.5'x0.3', little or no concentration. Precedes mag 8.5 SAO 63561 by 9'. NGC 5157 is 12' due west. NGC 5166B = MCG +05-32-027 is 4.5' NE and CGCG 161-060 is 5' SSW. NGC 5166B was logged as "extremely faint, very small, round, 20" diameter" and CGCG 161-060 as "extremely faint and small, round, 12" diameter. Located 1.5' NE of a mag 13 star."

Notes by Steve Gottlieb