Abell 2634 and 2666 – my god, it’s full of galaxies

About the Object

This is an at first sight rather unspectacular image of an area about 5 degrees across. NGC7741, a barred spiral in the middle of the lower half probably the most prominent object in this area. But dig deeper and zoom around and you find tons of galaxies. The image is focussed on the area of Abell 2634 (upper right quadrant), which is at a distance of some 450 Mly and, at slightly lower redshift (350Mly), Abell 2666 (upper left quadrant). Abell 2634 features a large cD galaxy - NGC7720. Both clusters are located in a region of complex structure in the background of the Pisces-Perseus supercluster with several further subunits, e.g. Abell 2622, which itself is a cluster in projection near the center of A2634 but at a distance of about 850 Mly. And indeed, while A2635 and A2666 features some 50-100 galaxies each, the overall structure is much richer: PGC and NGC list almost a thousand galaxies in this area, they are marked in revision B (hover over the image) - and remarkably, for almost every object in those catalogues, there is an optical identification (only a few pixels usually but often clearly an extended object (in particular for the edge-on disks)) in my image - quite remarkable for a 72mm scope and a shot from the balcony in suburbia.

Observation Notes

Data processing was challenging as one reaches the limits of such a small scope. Drizzling x2 helped to work out the barely resolved structure with BXT (sorry for the correspondingly large file size). There is also some barely resolved Galactic cirrus in the frame (in particular near the upper right corner), working that one out but simultaneously keeping noise under control was not easy.

Data were taken on 2023 September 23 and 24

Technical Details

View the full-resolution image together with complete acquisition and processing details on AstroBin.