NGC 7547, 7549, 7550 and 7558 are forming a close and partly interacting group of galaxies in the constellation of Pegasus in a distance of 220-240 million light-years.
The group is also known as ARP 99 and Hickson 93.
Tidal interactions from an ancient collision can be seen as Shells surrounding NGC 7550.
LRGB (500-140-140-140 min) total 15 h, north is up, seeing 0.8-1.3 arc-sec,
80cm f/7 Astrooptik Keller cassegrain, FLI PL-16803, Astrodon gen2 filters, Prompt 7 CTIO Chile
Processing: Johannes Schedler
Find here a wide image in 30/70% size and a center crop in 50/100% size below and at an inverted b/w image at bottom.