Arp 90

North is up (mirrored, exact). 0.53"/px [15' x 9.2' field]. FWHM = 3.9" Arp 90 is the two interacting galaxies in the east. The west of the image has a wierd distorted galaxy (?), with a similar redshift to the interacting pair. This means it could be a tidal fragment, or a gravitationally bound irregular galaxy... I really don't know. Total exposure time:314 * 30 seconds = 2.6 hours. Used in stack:276 * 30 seconds = 2.3 hours. Telescope: C9.25 (230mm, f/10, fl=2300mm) + 0.63 Starizona reducer Camera: IMX533 (16mm diagonal, square, color) Processing: Callibration (dark + flat) Stacking (average w/ outlier rejection) White balance and background subtraction (no gradient removal) Asinh stretch (color preserving) Rotation + crop Tone curve Taken during one night, with typical (ML-free) processing... except I rotated the image before cropping to align it to north. This should make it easier to cross reference. Related: https://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp90.jpeg: Arp's…