Abell 2151 (the Hercules Cluster) is a group of about 200 galaxies located approximately 509 million light-years away in Hercules. This 25x19 arc minute image shows four sets of Arps:
Arp 71 consists of perturbed spiral NGC 6045 (UGC 10177 and others) along with NGC 6045B (PGC 84720 and others), a HSB companion on the eastern edge of NGC 6045’s arm.
Arp 122 consists of spiral NGC 6040 (NGC 6040B, UGC 10165, VV 212/a and others) along with elliptical (?) NGC 6039 below it. Arp has these in his ‘ellipticals close to perturbing spirals’ class.
Arp 172 consists of IC 1178 (UGC 10188, VV 194a and others) interacting with IC 1181 (UGC 10189, VV 194b and others). This grouping is part of the ‘diffuse counter-tails’ class.
Arp 272 consists of NGC 6050 (UGC 10186, VV 220a and others) along with IC 1179 (NGC 6050B, VV 220b and others). These spirals are in the ‘connected arms’ class.
See the annotated versions for the locations of these groups.
Luminance – 24x600s – 240 minutes – binned 1x1
RGB – 8x300s – 40 minutes each – binned 2x2
360 minutes total exposure – 6 hours
Imaged April 16th and May 9th, 10th and 11th, 2016 from Dark Sky New Mexico at Rancho Hidalgo (Animas, New Mexico) with a SBIG STF-8300M on an Astro-Tech AT12RCT at f/8 2432mm.
LRGB - https://www.flickr.com/photos/dcrowson/40890496480/sizes/l
LRGB Annotated - https://www.flickr.com/photos/dcrowson/40890496210/sizes/l
LRGB PixInsight Annotated - https://www.flickr.com/photos/dcrowson/28826196738/sizes/l