400/500mm - 17.5" (4/4/92): faint, small, elongated 3:2 WSW-ENE. A mag 13 star is at the SW edge 0.6' from center. Located 12' ESE of mag 8.3 SAO 118800 in the NGC 3640 group with NGC 3643 12' N. A very faint quartet of galaxies is midway between NGC 3644 and NGC 3643.

600/800mm - 24" (5/20/20): at 375x; fairly faint, fairly small, oval 2:1 SW-NE, broad weak concentration. A mag 12.5 star is just off the SW edge. IC 683 and CGCG 039-134 (1.3' pair) lie 3.6' S and 4 members of Shkh 352 were seen 5' N. IC 683: faint, round, 20" diameter, very small brighter nucleus.

CGCG 039-134: extremely faint, round, 15" diameter, only occasionally popped

900/1200mm - 48" (4/4/11): moderately bright, moderately large, elongated 5:2 SW-NE, 40"x16", contains a bright core. A mag 12.5 star is 40" SSW of center. Shkh 352, a rich group of faint galaxies, lies 5' N in the field.