Hickson Galaxy Groups

Hickson Galaxy Groups
By Steve Gottlieb

The following observations were made during the past couple of weekends with my 17.5" at my favorite dark sky site in the Sierra foothills with observing buddies Jim Shields and Ray Cash. Good finder charts and moderate-high magnifications are helpful as these groups are very small but make a great observing project!

Steve Gottlieb

Hickson Group Observations
Name RA Dec Description
Hickson 55 11 32.1 +70 49 At 220x Hickson 55 appears as an extremely faint, elongated string SSW-NNE about 1' in length. Faint enough to require averted vision but appears irregular. At 280x, a couple of individual components (A and either B or C) are sometimes resolved with the more obvious "knot" at the N end of the string (Hickson 55a) appearing barely nonstellar. This well known chain contains a discordant redshift (55e) and is located 25' NW of N3735.
Hickson 69 13 55.5 +25 04 The brightest member of Hickson 69 group appears very faint, small, elongated 2:1 E-W, very low even surface brightness. Requires averted vision and concentration to see elongation clearly. The "b" component lies 1.5' S and is an extremely faint spot about 15" diameter. It's situated just following the midpoint of a line connecting two mag 15 stars 0.8' S and 0.9' NW. The "c" member is just a 10" knot glimpsed with averted vision 0.8' following Hickson 69a. Surrounded by a cluster of faint IC galaxies and viewed IC's 4342, 4343, 4344, 4345, 4346, 4348, 4349.
Hickson 71 14 11.0 +25 30 IC 4381 is the brightest member of Hickson 71 in a trio with IC 4382 = Hickson 71b 1.8' NE and Hickson 71c 2.0' SE. IC 4381 appears faint, round, 0.8' diameter, almost even surface brightness. Located 1.5' N of a mag 10 star. Hickson 71b appears to have a higher surface brightness than 71a and is elongated nearly 3:1 N-S, 0.8'x0.3'. The "c" component is another 15" knot forming a near equilateral triangle 2.3' SSE of IC 4382 and 2.0' ESE of IC 4381. It's possible that Hickson 71d was also momentarily glimpsed but not verified with any confidence.
Hickson 75 15 21.5 +21 11 CGCG 135-50 is the brightest of 3 or 4 visible in the faint Hickson 75 group. It appeared faint, fairly small, irregularly round. Hickson 75b is attached on the N side (edge-on) and was not seen with any certainty, although the galaxy seemed irregular or double on a couple of moments. Located 1.0' SW of a mag 12 star. The remaining members were all difficult - The "d" member is located 1.7' ESE of Hickson 75a and was just a 15" knot requiring averted vision and concentration. Even fainter was the "e" member which was just glimpsed on occasion 1' N of a mag 15 star and 1' SE of Hickson 75a. Hickson 75c was also possibly seen but the observation was confused with nearby 75d.
Hickson 77 15 49.3 +21 49 Hickson 77a = U10049 and 77b appear as an extremely faint, elongated glow measuring 30"x15" in a N-S orientation. A mag 15 star is 1' SE and a slightly fainter star 1.3' E. For moments only, resolved into two components (77a and 77b have a total length of 0.5') although extremely difficult to view these simultaneously.
Hickson 78 15 48.3 +68 13 Hickson 78a = U10057 appears very faint, elongated 3:1 E-W, 1.0'x0.3' with an even surface brightness. Forms a close double with Hickson 78b 1.2' SW which at first glance appeared roundish and ~30" diameter but with a higher surface brightness than 78a. With averted vision, very faint extensions are intermittently visible oriented SSW-NNE.
Hickson 80 15 59.3 +65 14 The brightest member of Hickson 80 (CGCG 319-38) is very faint, elongated 5:2 SW-NE, ~40"x15" with a low even surface brightness. In a tight trio with Hickson 80b just 38" S and Hickson 80c 1.2' W. The "b" component is an extremely faint knot about 10" diameter which is sandwiched between 80a close N and two mag 15 stars 1.2' and 1.8' S. The "c" component is a threshold object at 220x (easier at 280x) requiring averted vision to glimpse but possibly elongated. Situated 1.2' W of Hickson 80a.
Hickson 84 16 44.4 +77 50 Hickson 84a = CGCG 355-20 appears very faint, slightly elongated N-S, ~30"x25". Located 2.1' SE of a mag 11 star and forms the northern vertex of a small isosceles triangle with two mag 15 stars 0.7 WSW and SSE. Hickson 84b lies 1.3' NNW and is a marginal object at 280x, glimpsed for moments 1.2' E of a mag 11 star and 1.3' NNW of 84a. Appears extremely small, possibly elongated NW-SE but view may be confused by an extremely faint star attached at the NW end.

Name	RA	Dec	Description
Hickson 55	11 32.1	+70 49	At 220x Hickson 55 appears as an extremely faint, elongated string SSW-NNE about 1' in length. Faint enough to require averted vision but appears irregular. At 280x, a couple of individual components (A and either B or C) are sometimes resolved with the more obvious "knot" at the N end of the string (Hickson 55a) appearing barely nonstellar. This well known chain contains a discordant redshift (55e) and is located 25' NW of N3735.
Hickson 69	13 55.5	+25 04	The brightest member of Hickson 69 group appears very faint, small, elongated 2:1 E-W, very low even surface brightness. Requires averted vision and concentration to see elongation clearly. The "b" component lies 1.5' S and is an extremely faint spot about 15" diameter. It's situated just following the midpoint of a line connecting two mag 15 stars 0.8' S and 0.9' NW. The "c" member is just a 10" knot glimpsed with averted vision 0.8' following Hickson 69a. Surrounded by a cluster of faint IC galaxies and viewed IC's 4342, 4343, 4344, 4345, 4346, 4348, 4349.
Hickson 71	14 11.0	+25 30	IC 4381 is the brightest member of Hickson 71 in a trio with IC 4382 = Hickson 71b 1.8' NE and Hickson 71c 2.0' SE. IC 4381 appears faint, round, 0.8' diameter, almost even surface brightness. Located 1.5' N of a mag 10 star. Hickson 71b appears to have a higher surface brightness than 71a and is elongated nearly 3:1 N-S, 0.8'x0.3'. The "c" component is another 15" knot forming a near equilateral triangle 2.3' SSE of IC 4382 and 2.0' ESE of IC 4381. It's possible that Hickson 71d was also momentarily glimpsed but not verified with any confidence.
Hickson 75	15 21.5	+21 11	CGCG 135-50 is the brightest of 3 or 4 visible in the faint Hickson 75 group. It appeared faint, fairly small, irregularly round. Hickson 75b is attached on the N side (edge-on) and was not seen with any certainty, although the galaxy seemed irregular or double on a couple of moments. Located 1.0' SW of a mag 12 star. The remaining members were all difficult - The "d" member is located 1.7' ESE of Hickson 75a and was just a 15" knot requiring averted vision and concentration. Even fainter was the "e" member which was just glimpsed on occasion 1' N of a mag 15 star and 1' SE of Hickson 75a. Hickson 75c was also possibly seen but the observation was confused with nearby 75d.
Hickson 77	15 49.3	+21 49	Hickson 77a = U10049 and 77b appear as an extremely faint, elongated glow measuring 30"x15" in a N-S orientation. A mag 15 star is 1' SE and a slightly fainter star 1.3' E. For moments only, resolved into two components (77a and 77b have a total length of 0.5') although extremely difficult to view these simultaneously.
Hickson 78	15 48.3	+68 13	Hickson 78a = U10057 appears very faint, elongated 3:1 E-W, 1.0'x0.3' with an even surface brightness. Forms a close double with Hickson 78b 1.2' SW which at first glance appeared roundish and ~30" diameter but with a higher surface brightness than 78a. With averted vision, very faint extensions are intermittently visible oriented SSW-NNE.
Hickson 80	15 59.3	+65 14	The brightest member of Hickson 80 (CGCG 319-38) is very faint, elongated 5:2 SW-NE, ~40"x15" with a low even surface brightness. In a tight trio with Hickson 80b just 38" S and Hickson 80c 1.2' W. The "b" component is an extremely faint knot about 10" diameter which is sandwiched between 80a close N and two mag 15 stars 1.2' and 1.8' S. The "c" component is a threshold object at 220x (easier at 280x) requiring averted vision to glimpse but possibly elongated. Situated 1.2' W of Hickson 80a.
Hickson 84	16 44.4	+77 50	Hickson 84a = CGCG 355-20 appears very faint, slightly elongated N-S, ~30"x25". Located 2.1' SE of a mag 11 star and forms the northern vertex of a small isosceles triangle with two mag 15 stars 0.7 WSW and SSE. Hickson 84b lies 1.3' NNW and is a marginal object at 280x, glimpsed for moments 1.2' E of a mag 11 star and 1.3' NNW of 84a. Appears extremely small, possibly elongated NW-SE but view may be confused by an extremely faint star attached at the NW end.