Hickson 51 observation

Hickson 51 observation
By Steve Gottlieb

Rich Jakiel recently posted [on s.a.a.] his observations of Hickson 56 including the detached edge-on next to the chain:

>Component "a" was a very faint, edge-on, measuring ~ 20" by 5", and
>oriented nearly north-south. It was considerably more difficult to discern
>than the components associated with the strand.

Neither Ray Cash or I had a definite sighting of the edge-on with our 17.5" scopes although the main chain was resolved with careful attention. So, this galaxy is probably a good test for similar-sized scopes.

Besides taking a look at Hickson 67 (which also has a faint thin edge-on!) and Copelandšs Septet, I also observed the Hickson 51 group which has 5 galaxies within a 4š circle. The two brightest members, NGC 3651 and 3653 were discovered by William Herschel and reobserved later by his son, John and itšs a bit surprising they missed all three fainter members. The positions below are from HGSC for J2000.
The Hickson 51 Group
Name RA Dec Name Description
MCG +04-27-027 11 22 13.3 +24 19 01 Hickson 51e faint, very small, round, 20" diameter, moderate surface brightness. Forms a close pair with IC 2759 1.0' S. A mag 13 star lies 2.0' NW. Located 3.2' NW of brightest member N3651.
IC 2759 11 22 14.2 +24 18 00 Hickson 51b very faint, fairly small, elongated 3:2 N-S, 0.9'x0.6', very weak concentration. Larger of close pair with M+04-27-027 1.0' N. This galaxy has a lower surface brightness than M+04-27-027.
NGC 3651 11 22 26.4 +24 17 56 Hickson 51a brightest member of the Hickson 51 quintet. Fairly faint, fairly small, slightly elongated N-S, 1.0'x0.8', small brighter core. Forms a small isosceles triangle with N3653 (51c) 1.4' SE and MCG +04-27-030 (51d) 1.0' E. IC 2759 (51B) lies 2.7' W.
NGC 3653 11 22 30.1 +24 16 45 Hickson 51c faint, small, slightly elongated E-W, 30" diameter, stellar nucleus. Second brightest in Hickson 51 quintet.
MCG +04-27-030 11 22 30.6 +24 18 00 Hickson 51d extremely faint, extremely small, 12" diameter. Faintest of 5 in Hickson 51. In a tight trio, located 1.0' E of N3651 and 1.2' N of N3653.

*The Hickson 51 Group*
Name	RA	Dec	Name	Description
MCG +04-27-027	11 22 13.3	+24 19 01	Hickson 51e	faint, very small, round, 20" diameter, moderate surface brightness. Forms a close pair with IC 2759 1.0' S. A mag 13 star lies 2.0' NW. Located 3.2' NW of brightest member N3651.
IC 2759	11 22 14.2	+24 18 00	Hickson 51b	very faint, fairly small, elongated 3:2 N-S, 0.9'x0.6', very weak concentration. Larger of close pair with M+04-27-027 1.0' N. This galaxy has a lower surface brightness than M+04-27-027.
NGC 3651	11 22 26.4	+24 17 56	Hickson 51a	brightest member of the Hickson 51 quintet. Fairly faint, fairly small, slightly elongated N-S, 1.0'x0.8', small brighter core. Forms a small isosceles triangle with N3653 (51c) 1.4' SE and MCG +04-27-030 (51d) 1.0' E. IC 2759 (51B) lies 2.7' W.
NGC 3653	11 22 30.1	+24 16 45	Hickson 51c	faint, small, slightly elongated E-W, 30" diameter, stellar nucleus. Second brightest in Hickson 51 quintet.
MCG +04-27-030	11 22 30.6	+24 18 00	Hickson 51d	extremely faint, extremely small, 12" diameter. Faintest of 5 in Hickson 51. In a tight trio, located 1.0' E of N3651 and 1.2' N of N3653.

It appears that all modern catalogues identify IC 2759 = MCG +04-27-026 = CGCG 126-040. which forms a 1' pair with MCG +04-27-027 = CGCG 126-041. In contrast to the Hickson letter designations, I found MCG +04-27-027 to be visually more obvious than IC 2759 due to a higher surface brightness.

Itšs possible that MCG, CGCG and RC3 have the wrong IC designation. As IC 2759 was discovered visually (by Bigourdan), Išd be interesting in hearing other reports on which one of these close galaxies were more prominent.