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View Full Version : Observations of KTG Triplets - part 1 (11 May 2013)



Steve Gottlieb
May 16th, 2013, 07:42 PM
Last Saturday night, I met up with Mark Wagner, his wife Mina, Richard Navarette, as well as Deep Sky Forum members Mark Johnston and Carter Scholz at Kevin Ritschel's "Deep Sky Ranch" southeast of Hollister in central California. Kevin wheeled out his monster-sized 33.4-inch f/5.1, which towered over my 24-inch f/3.7. Conditions were a mixed bag -- they looked awful in some parts of the sky (generally low on the horizons), but could be surprisingly good in other parts. SQM readings varied from 21.3 to 21.6.

I really had just one observing project, continue working through the 84 KTG trios from the 1979 "Isolated Galaxy Triplets" catalogue by Karachentseva, Karachentsev and Shcherbanovsky. While observing together recently, I've got Carter Scholz hooked on going through this catalogue with his new 16-inch f/4.5, so I believe we were probably looking at some of the same objects. Also, Alvin Huey describes most, if not all, of the groups below, in various observing reports (http://www.faintfuzzies.com/ObservingReports.html) over the past couple of years at faintfuzzies.com

The following observations were made with my 24-inch f/3.7 Starstructure at 375x, which was about the highest power the seeing would consistently allow. The variable transparency probably contributed to my missing a couple of the fainter, low surface brightness members (the photographic limit is nominally 15.7), but in one case an annoying superimposed star was also the culprit. The size listed below is the maximum separation of any of the members in each trio.

KTG 40
11 58 43 +42 39 08
Size 10.2'
IC 750 = KTG 40B appeared bright, fairly large, very elongated 3:1 SW-NE, 1.5'x0.5', well-concentrated with a bright, elongated core that gradually increases to the center. A mag 16 star lies 1' S of center. Forms an usual 3.4' pair with IC 749 = KTG 40A, which is a Sc face-on with a much lower surface brightness. IC 749 appeared moderately bright, large, slightly elongated ~N-S, 1.3'x1.1', diffuse appearance with an ill-defined halo due to low surface brightness around periphery. But the surface brightness appeared irregular or mottled with a very small, slightly brighter nucleus and an impression of spiral structure. The SDSS image resolves the spiral arms into numerous blue HII regions and that probably contributed to the visual impression of mottling. Mag 8.9 HD 103954 lies 3.1' SW. IC 751 = KTG 40C, located 10' S, appeared fairly faint to moderately bright, very elongated 7:2 SSW-NNE, 40"x12". Sharply concentrated with a very small bright nucleus. Forms a pair with IC 752 4.1' E (not part of the KTG 40 triplet). IC 751's redshift is 10x that of IC 749 and IC 750, so there are apparently two physical pairs of galaxies (along with IC 751/752) in the eyepiece.
644

KTG 41
12 04 45.3 +31 10 31
Size 2.0'
This small triplet (total size 2') consists of UGC 7064, CGCG 158-11 (very close pair) and CGCG 158-12. The trio is located 9' WSW of mag 8.3 HD 104998. At 375x UGC 7064 = KTG 41A appeared moderately bright, fairly small, round, 30" diameter, gradually increases to a small bright nucleus. A mag 10 star lies 2.8' S, but did not affect observation of the trio. CGCG 158-011 = KTG 41C (double system) is 0.9' NNW and appeared faint to fairly faint, small, round, 18". CGCG 158-010 = KTG 41B is 1.1' SSE of UGC 7064 and was the faintest member of the triplet and appeared very faint/faint, very elongated 3:1 NNW-SSE, 24"x8". This trio also is catalogued as Rose 8.
645

KTG 46
13 18 16 +04 26 42
Size 10.2'
Nice 10' string of three IC galaxies oriented SW to NE. At 375x IC 871 = KTG 46A appeared fairly faint, elongated 2:1 WSW-ENE, 0.8'x0.4', sharply concentrated with a bright core and diffuse halo. A mag 12 star lies 1.3' E. IC 873 = KTG 46B, situated 5.7' NE, appeared fairly faint, small, round, 18", weak concentration. Compact galaxy with a moderately high surface brightness. IC 876 = KTG 46C, 4.8' ENE, appeared fairly faint, fairly small, elongated 4:3 N-S, 24"x18", weak concentration, small brighter nucleus.
646

KTG 47
13 38 34 +00 31 42
Size 3.5'
This triplet is dominated by IC 904 = KTG 47B which appeared moderately bright and large, elongated 2:1 NW-SE, 40"x20", fairly high surface brightness, brighter nucleus. Much fainter UGC 8631 = KTG 47C lies 1.9' E and CGCG 17-46 = KTG 47A is 2.0' SSW. CGCG 17-46 appeared extremely faint, very small, 15"x6", required averted to glimpse. A mag 16 star lies 25" SSW. UGC 8631 was also extremely faint, fairly small, elongated 2:1 E-W, 0.4'x0.2', very low surface brightness. Situated 1.9' E of IC 904 and 1.4' W of a mag 12.5 star. The trio spans 3.5' SW to NE.
647

KTG 48
13 43 52 +03 53 48
Size 6.2'
UGC 8686 = KTG 48A is first in the KTG triplet and forms a close pair with CGCG 45-81 1.2' SE. At 375x it appeared fairly faint, moderately large, very elongated 4:1 SW-NE, 0.8'x0.2', weak concentration. CGCG 45-81 = KTG 48B appeared faint, very small, round, 12" diameter, no details. Lastly, CGCG 45-84 = KTG 48C, located ~6' E of the pair, appeared fairly faint, fairly small, elongated 2:1 WNW, 30"x15", sharply concentrated with a bright round nucleus. A mag 13.3 star lies 1.1' WSW.
648

KTG 49
13 46 18 -03 24 00
Size 3.1'
This triplet consists of a close pair (CGCG 17-67 = KTG 49B and 49C) and a very diffuse, low surface brightness spiral (CGCG 17-67 = KTG 49A). At 375x, KTG 49B appeared fairly faint, fairly small, elongated 2:1 N-S, 25"x12". Forms a close pair with KTG 49C 0.8' NNE. KTG 49C appeared faint, very small, slightly elongated, high surface brightness, 15"x12" diameter. Based on the SDSS image, I picked up the core of this sharply concentrated galaxy. A mag 15.2 star lies 0.8' NNE. KTG 49A = CGCG 17-67 appeared extremely faint, small, round, 18" diameter, very low even surface brightness, requires averted to glimpse at 375x.
649

KTG 51
13 57 16 +11 59 54
Size 3.1'
KTG 51 consists of high surface brightness IC 962 and two CGCG galaxies, extending just 3.1' NW to SE. At 375x, IC 962 = KTG 51A appeared fairly bright, fairly small, round, 24", small bright nucleus, high surface brightness. First in the triplet with CGCG 74-14 1.4' S and CGCG 74-16 3.1' SE. Located 8.7' NW of mag 7.7 HD 121845. KTG 51B = CGCG 74-14 appeared fairly faint, fairly small, elongated 3:2 NNW-SSE, 0.4'x0.25', sharply concentrated with a very small bright nucleus and a diffuse halo. KTG 51C = CGCG 74-16 lies 1.8' SE and appeared faint to fairly faint, small, round, weak concentration, 18" diameter, small slightly brighter core.
650

KTG 52
14 02 08.9 -01 22 38
Size 2.5'
UGC 8939 = KTG 52A is the brightest member of the KTG 52 triplet. At 375x it appeared fairly faint to moderately bright, round, 35" diameter, broad concentration. CGCG 18-29 = KTG 52B lies 3.3' SSE and CGCG 18-31 = KTG 52C is 2.6' SE. CGCG 18-29 appeared fairly faint, small, round, high surface brightness, 18", stellar nucleus. CGCG 18-31 was not confirmed, although thin clouds probably affected the observation.
651

KTG 53
14 04 34 +16 18 18
Size 8.1'
CGCG 103-060= KTG 53B is the brightest member of this triplet. At 375x it appeared faint to fairly fairly, small, slightly elongated, compact, fairly high surface brightness, 18"x15". CGCG 103-65 = KTG 53C lies 5.6' ESE and appeared extremely faint, very small, round, 15" diameter, low even surface brightness. A mag 11.4 star lies 2.8' ENE. UGC 8987 = KTG 53A, a very low surface brightness edge-on (interacting?), was not seen.
652

KTG 54 = Arp 286
14 20 18 +03 58 12
Size 7'
NGC 5560 = KTG 54A appeared fairly bright, fairly large, very elongated 7:2 WNW-ESE, 2.0'x0.6', relatively large bright core, fades and tapers towards tips. First in a trio with NGC 5560 5.3' SE and much fainter NGC 5569 7' E (the trio forming Arp 286 = KTG 54). A mag 14 star is 40" N of center and mag 8.2 HD 125505 is 5' WNW. NGC 5566 = KTG 54B appeared very bright, very large, very elongated 3:1 SW-NE. Very sharply concentrated with a large, bright elongated core that is also sharply concentrated with an intense elongated nucleus, angled with respect to the major axis. The halo is very diffuse without a sharp edge, but extends at least 4.0'x1.3'. The core is bracketed by mag 12 and 14 stars to the east and west, respectively. Finally, NGC 5569 = KTG 54C was surprisingly low surface brightness in the 24" and appeared as a faint, fairly large, very diffuse glow with a very weak core, slightly elongated, ~1.2'x1.0'.
653