John Herschel discovered NGC 3561 = h835 on 30 Mar 1827 (sweep 65) and simply noted "vF. The last of a group of 4 [with NGC 3550, 3552 and 3554]." The next night he called it "F; pL; 8' dist from another NGC 3550] and 30° south-following it." He likely picked up the brighter southern component of this multiple system.

RC2 lists the components as NGC 3561A = MCG +05-27-011 (northern) and NGC 3561B = MCG +05-27-010 (southern). The dwarf galaxy "Ambartsumian's knot" is located at the southern end of a plume extending from NGC 3561B.

300/350mm - 13.1" (3/24/84): very faint, very diffuse spot with averted. This member of AGC 1185 is slightly larger than most members.

900/1200mm - 48" (5/12/12): bright, fairly small, round, 0.6' diameter, small bright core. Forms a close pair with NGC 3561A 0.9' N. The companion appeared fairly bright, fairly small, elongated 3:2 NNW-SSE, 30"x20", small bright core.

At 488x, a very low surface extension or plume reaches 30" S. The dwarf galaxy "Ambartsumian's Knot" was occasionally visible near its southern end as an extremely faint stellar spot. A number of galaxies within AGC 1185 are nearby including MCG +05-27-012 1.6' SW, which appeared fairly faint, fairly small, elongated 3:2 SSW-NNE, 0.3'x0.2'.

MCG +05-27-012, 1.6' SE of NGC 3561, is fairly faint, fairly small, elongated 3:2 SSW-NNE, 0.3'x0.2'. 2MASX J11112084+2840183, 2.2' SE of NGC 3561 and 39" SE of MCG +05-27-012, appeared faint, small, elongated 2:1 SW-NE, 16"x8".

Notes by Steve Gottlieb