Although most of our time and energy last Saturday at Fiddletown was spent on the mundane tasks of keeping equipment and charts as dry as possible (thanks Allan for the hair dryer!), I spent observing time looking at tightly packed Hickson groups and a meandering across a huge supercluster in the southern sky.
Sprawling across 60 degrees of southern sky (roughly east-west) from Antlia to Centaurus are a number of galaxy clusters comprising the Hydra-Centaurus Supercluster. This is a relatively nearby supercluster with quite a number of mag 13 and brighter member and would probably be a popular star party target if it was placed more northerly in the sky. The best galaxy groups in the supercluster include Hydra I (Abell 1060), IC 4329 (Abell 3574), Centaurus cluster (Abell 3526), IC 4296 (Abell 3565) and the Antlia Group (NGC 3258- NGC 3289). These are all rich, rewarding clusters in 10" and larger scopes and are accessable from Northern California with a little effort. The brightest and richest cluster, Abell 3526, is down at -41 degrees declination, but I've still logged two dozen members from Fiddletown. Jim Shields and I have info on the supercluster at Adventures in Deep Space, http://redshift.home.pipeline.com/superso.htm
The IC 4296 group resides in northern Centaurus, just four degrees south of M83. The brightest member, IC 4296 (V = 10.6!), was discovered by Lewis Swift using a 16" refractor in southern California on December 30, 1897 although John Herschel had swept through the cluster from the Cape of Good Hope in the 1830's and only picked up two fainter members, NGC 5215 and NGC 5220. Swift, also recorded a fainter companion, IC 4299, but missed most of the cluster. Although the 95+% humidity made things more challenging, I didn't have too much trouble picking up a number of ESO galaxies in the cluster.
ESO 383-025 = M-06-30-010
13 34 46.7 -34 18 44
V = 13.0; Size 1.3x1.0; SB = 13.2; PA = 30d
17.5": faint, oval 4:3 SSW-NNE, 0.7'x0.5', fairly low even surface brightness. A faint pair, E383-031/032, lies 10' NE.
NGC 5215A = E383-IG28 = M-05-32-040 = VV 693
13 35 06.7 -33 28 53
V = 13.1; Size 0.6x0.5; SB = 11.7; PA = 105d
17.5": western component of double system with N5215[B]. Ths member appears faint, very small, 20", stellar nucleus. N5215[B] follows by 20".
NGC 5215 = E383-IG29 = M-05-32-041 = VV 693
13 35 09.5 -33 29 02
V = 12.9; Size 1.1x0.5; SB = 12.1; PA = 70d
17.5": this double system consists of a two faint, very small galaxies separated by 20" E-W. The following member (described by John Herschel) is slightly elongated. Both galaxies have sharp, stellar nuclei. A mag 14 star lies 42" due south of the eastern component. Located 12' SE of a mag 6.5 star.
ESO 383-030 = M-05-32-043 = A1332-33
13 35 17.7 -33 53 55
V = 13.2; Size 1.4x0.9; SB = 13.2; PA = 178d
17.5": very faint, small, elongated 2:1 N-S, 0.8'x0.4'. A mag 14 star is at the south edge, 25" from the center.
ESO 383-031 = M-06-30- 013
13 35 21.3 -34 12 23
V = 13.7; Size 1.2x0.6; SB = 13.2; PA = 83d
17.5": extremely faint, small, elongated 3:2, 0.6'x0.4' E-W. Forms a pair with E383-032 2.7' N.
ESO 383-032 = PGC 47913
13 35 23.0 -34 09 40
V = 14.4; Size 0.9x0.6; SB = 13.6; PA = 108d
17.5": extremely faint, very small, round, 0.4', low surface brightness. Forms a pair with E383-031 2.7' S.
NGC 5220 = E383-036 = MCG -5-32-46
13 35 57.0 -33 27 13
V = 12.2; Size 2.3x0.7; SB = 12.6; PA = 97d
17.5": fairly faint, moderately large, elongated 5:2 E-W, 1.5'x0.6'. A mag 13 star is at the following end [52" from center] and a mag 14.5 star is just north of central region. A mag 9.1 star lies 2.8' SE. NGC 5215 (pair) lies 10' W. Located 17' SE of mag 6.6 HD 118010. Dust lane (similar to Sombrero) not seen.
IC 4296 = E383-039 = M-06-30-016
13 36 39.1 -33 57 59
V = 10.6; Size 3.4x3.2; SB = 13.2
17.5": moderately bright, moderately large, at least 2' diameter, round, bright core, stellar nucleus. Brightest in Abell 3565 and group LGG 353 (part of Centaurus-Hydra supercluster). Forms a pair with IC 4299 6' SSE.
IC 4299 = E383-042 = M-06-30-017
13 36 47.5 -34 03 58
V = 12.6; Size 1.8x0.6; SB = 12.6; PA = 58d
17.5": fairly faint, fairly small, elongated 3:2 SW-NE, 1.2'x0.8'. Moderate concentration with a small brighter core. Located 6' SSE of IC 4296.
If you observe this group, make sure and check out the IC 4329 cluster (Abell 3574), about four degrees northeast. At the western edge of the cluster is the interacting, distorted pair NGC 5291 and MCG -5-33-5, better known as the "Seashell" galaxy for its "whelk" appearance. Deep photographs reveal plumes of material extending from the tidal disturbance stretching some 600,000 light years! John Herschel made a fairly comprehensive tour of the cluster, recording NGC 5291, 5292, 5298, 5302 and Swift added NGC 5304 but once again they missed the largest member, IC 4329.
MCG -05-33-005 = Seashell Galaxy
13 47 23.3 -30 25 01
Size 0.4x0.1
17.5": very faint, very small, round. Nearly attached to the S end of N5291 in the IC 4329 cluster (Abell 3574). Known as the "Seashell" galaxy due to distorted appearance on photographs.
NGC 5291 = E445-030 = M-05-33-006
13 47 24.4 -30 24 28
V = 14.1; Size 1.1x0.7; SB = 13.8; PA = 168d
17.5": fairly faint, very small, round, small bright core. Forms a double system with M-05-33-005 = "Seashell galaxy" just 0.6' S.
NGC 5292 = E445-031 = M-05-33-008
13 47 39.6 -30 56 20
V = 11.9; Size 1.8x1.5; SB = 12.9; PA = 55d
17.5": moderately bright, fairly small, gradually brighter halo, bright core. Two mag 13-14 stars are collinear to the NE (the closer star is 1.0' from center).
MCG -05-33-009
13 48 06.1 -30 32 12
V = 13.9; Size 0.7x0.5; SB = 12.6
17.5": extremely faint, very small, round. Forms a pair with E445-037 3' SE. Located 5.2' S of N5298.
E445-035 = M-05-33-010
13 48 11.1 -30 27 08
V = 13.1; Size 1.1x0.8; SB = 12.9; PA = 166d
17.5": faint, small, slightly elongated, weak concentration. Located in a group of faint stars. The M-05-33-009/E445-037 pair lies 5' S and N5298 = E445-039 is 5.7' ENE.
ESO 445-037 = M-05-33-011
13 48 15.8 -30 34 30
V = 14.4; Size 1.1x0.4; SB = 13.4; PA = 54d
17.5": faint, very small, oval, small bright core. Several stars lie S. Forms a pair with M-05-33-009 2.0' WNW. Located 7' S of N5298 in the IC 4329 cluster.
NGC 5298 = E445-039 = M-05-33-015
13 48 36.5 -30 25 43
V = 13.1; Size 1.4x0.7; SB = 12.9; PA = 69d
17.5": fairly faint, fairly small, oval SW-NE, weak concentration. E445-035 lies 5.7' WSW.
ESO 445-040 = A1345-30 = M-05-33-014
13 48 39.2 -30 48 39
V = 13.2; Size 1.5x0.4; SB = 12.5; PA = 88d
17.5": faint, fairly small, oval E-W. Located 7.5' SW of mag 7.7 SAO 204870. Member of the IC 4329 cluster (Abell 3574).
NGC 5302 = E445-043 = M-05-33-018
13 48 49.7 -30 30 40
V = 12.1; Size 1.8x1.1; SB = 12.7; PA = 153d
17.5": fairly faint, small, elongated SSW-NNE, bright core, faint stellar nucleus. Member of the IC 4329 cluster (Abell 3574).
IC 4329 = E445-046 = M-05-33-019
13 49 05.3 -30 17 45
V = 11.3; Size 3.4x1.9; SB = 13.2; PA = 63d
17.5": fairly faint, fairly small, oval WSW-ENE, bright core, stellar nucleus. Forms a pair with IC 4329A 3' E. This galaxy is the brightest in the IC 4329 cluster.
ESO 445-049 = M-05-33-020
13 49 09.4 -31 09 54
V = 12.5; Size 1.4x0.5; SB = 12.1; PA = 170d
17.5": faint, fairly small, elongated N-S. A mag 14 star is at the ESE edge 23" from the center. Forms a pair with M-05-33-017 (not seen).
IC 4329A = E445-050 = M-05-33-021
13 49 19.3 -30 18 34
V = 13.0; Size 1.4x0.4; SB = 12.2; PA = 45d
17.5": fairly faint, very small, slightly elongated SW-NE, sharp stellar nucleus. This Seyfert galaxy is located just 3' ESE of IC 4329.
NGC 5304 = E445-052 = M-05-33-022
13 50 01.5 -30 34 43
V = 12.6; Size 1.5x1.0; SB = 13.0; PA = 146d
17.5": faint, small, oval NW-SE, weak concentration. An equilateral triangle consisting of mag 14 stars is off the S side with components 44" S, 1.7' SSW and 2.2' SSE of center. Member of the IC 4329 cluster (Abell 3574).