Hickson Compact Groups 93 (with Arp 99) and 94 (with Arp 170)
About the Object
This rich galaxy field in the constellation Pegasus contains two particularly interesting compact galaxy groups. In the lower left, Hickson Compact Group 93 (HCG 93) includes NGC 7547, NGC 7549, NGC 7550, NGC 7553 and NGC 7558. At its heart, the peculiar spiral NGC 7549 and the bright lenticular NGC 7550 form Arp 99, a close interacting pair in which NGC 7549 shows pronounced distortion and extended spiral structure produced by gravitational encounters. NGC 7547 is also physically associated with the system, although it is not formally part of Arp 99. In the upper right lies the considerably more distant galaxy NGC 7578, also known as Arp 170, at about 550 million light-years. Arp 170 consists principally of the interacting galaxies NGC 7578A and NGC 7578B and forms the core of the still richer Hickson Compact Group 94 (HCG 94). Chip Arp included the pair in his Atlas of Peculiar Galaxies in the category of galaxies displaying diffuse counter-tails, structures produced by gravitational interaction.
Observation Notes
Data were taken on 2026 September 6, 11, 14, and 18
Technical Details
View the full-resolution image together with complete acquisition and processing details on AstroBin.
View on AstroBin ↗