Willhelm Tempel discovered NGC 4166 = T IX-10 on 15 Mar 1885 with the 11-inch refractor at Arcetri while searching for the periodic Comet 1867 II. Tempel's position is just 1' S of UGC 7198.

400/500mm - 17.5" (5/11/02): fairly faint, fairly small, round, 0.8' diameter, moderate concentration to a very small brighter core. Very symmetrical appearance.

Notes by Steve Gottlieb