Hickson Compact Group 99 consists of five galaxies in Pegasus:
UGC 12897 (HCG 99a, PGC 54 and others) is the spiral next to the bright star on the right side of the cluster.
UGC 12899 (HCG 99b, PGC 63 and others) is the elliptical to the left of the ring galaxy.
MCG+05-01-021 (HGC 99c, PGC 58 and others) is the ring galaxy to the right of UGC 12899.
PGC 60 (HCG 99d) is the small galaxy at the bottom left of the cluster.
PGC 57 (HCG 99e) is the small galaxy at the bottom right of the cluster.
See the annotated image for the locations of these and others.
Luminance – 24x600s – 240 minutes – binned 1x1
RGB – 12x300s – 60 minutes each – binned 2x2
420 minutes total exposure – 7 hours
Imaged over seven nights in October and November, 2022 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/52713355699/sizes/l/
LRGB annotated - https://www.flickr.com/photos/dcrowson/52713514475/sizes/l/