Arp 13 (NGC 7448, UGC 12294 and others) is a spiral galaxy located approximately 100 million light-years away in Pegasus. Arp has this one in the ‘Spiral galaxies with detached segments’ group. I’m guessing he was referring to the bright knots in the arms near the top of the galaxy.
Luminance – 24x600s – 240 minutes – binned 1x1
RGB – 8x300s – 40 minutes each – binned 2x2
360 minutes total exposure – 6 hours
Imaged August 21st, 24th and 27th, 2017 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/36034980234/sizes/l