Dr. Paul Hickson published a paper, “Systematic Properties of Compact Groups of Galaxies” in the Astrophysical Journal in 1982. This paper contained a list of 100 isolated compact group of galaxies ranging from quartets to octets. He used three main criterion to select his 100 groups; (1) Population - At least 4 members and all are within 3 magnitudes of each other, (2) Isolation – not part or near any larger groups, such as Abell Galaxy Clusters, (3) Compactness – Basically, only those that fairly compact would meet this criteria, of 26 mag/arcsec. His paper can be found here http://tinyurl.com/87b3aob
So after some time, amateur observers with large telescopes, started to take this “list” as a challenge list.
Steve Gottlieb already mentioned the history of the Arp Peculiar Galaxies. Dr. Halton Arp categorized Arp 214 as “Irregularities, absorption and resolution”
I’ve observed this group several times over the years. It is interesting to think that the Hickson group lies almost 10 times further away than Arp 214.
My observations are as follows:
Hickson 56 (22” f/4 reflector at 881x under NELM 6.5 skies)
One galaxy is separated from the rest (four other galaxies). The string of four, three visible, galaxies is in a string of about 60” long. This Group lies only 10’ south of NGC 3718, a very bright peculiar galaxy. Component A (MCG+9-19-113) shows as a faint spindle with an almost stellar nucleus. It is about 60” long and averted vision gives maybe about 5” longer spindle. PA = 0˚. Component B (UGC 6527) shows a small, faint, round disk with a diameter of about 15”. This forms a very close double galaxy with PGC 35618. This pair lies 1.5’ WNW from MCG+9-19-113. Component C (PGC 35618) lies less than 15” west of UGC 6527 and is a very faint round disk of about 10” in diameter. Component D (PGC 35615) – Not seen, but I’m not sure. Component E (PGC 35609) – At 880x, this nearly stellar galaxy is seen only 50% of the time. It is found sitting 40” WSW of PGC 35615.
Arp 214 (22" f/4.1 reflector @ 184, 255, 305 and 377x under NELM 6.5 skies)
This one is a weird one, but fun to look at. At first it looked like an elliptical with a dust lane screaming across the middle and cutting its compact nucleus in half. Studying this with higher powers showed very faint arms with the north one a little brighter, but shorter. The dust lane is at PA = 120º. The round part is 2.5’ across and the both arms extend as much as 1.5’ from the edge of the disk.
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