Although Arp 50 is supposedly an example of a spiral galaxy with a small, bright companion, there is no obvious brightening which might be associated with another galaxy; the irregular brightness appears to be intrinsic to the galaxy. Still, most catalogs list it as a galaxy pair, though without any indication of where the second galaxy is supposed to be. Based on its recessional velocity of 9025 km/sec, IC 1520 is about 400 million light years away. Given that and its apparent size of 0.5 by 0.5 arcmin, it is about 60 thousand light years across.

Apparent size 0.3 by 0.2 arcmins; nothing else appears to be available.

Per Dreyer, IC 1525 (= Swift's list IX (#100), 1860 RA 23 52 54, NPD 43 54.2) is "extremely faint, pretty small". The position precesses to RA 00 00 01.2, Dec +46 52 34, over 45 seconds of time east of the galaxy; but the galaxy is so obviously the only possible candidate, and the error so characteristic for Swift's later discoveries (Dreyer noted the excellent quality of Swift's earlier observations, but lamented their later deterioration), that no one seems to doubt the identification. Based on a recessional velocity of 5020 km/sec, IC 1525 is about 225 million light years away. Given that and its apparent size of 1.9 by 1.4 arcmin, it is about 125 thousand light years across. IC 1525 is listed as a member of Local Galaxy Group 485, which also contains PGC 2 and 676. It is also listed as a member of WBL729, a group with an average recessional velocity of about 5020 km/sec which also includes PGC 18 and 73195; so all five galaxies may be physically related. PGC 2, 18 and 73195 and IC 1525 are less than 30 arcmin apart, and if at nearly the same distance from us, may be within a region less than two million light years across; but PGC 676 is quite a bit further away, being about 2 1/2 degrees east of the other group members.

Per Dreyer, IC 1530 (= Bigourdan 357, 1860 RA 00 00 06, NPD 58 10) is "very faint, small, irregular figure, brighter middle". The position precesses to RA 00 07 18.2, Dec +32 36 46, only about 0.3 arcmin northwest of the center of the galaxy, so the identification is certain. However, (as noted at NGC 7831, which see for images and a discussion of the object) Swift's position was off by more than a second of time and 8 arcmin of declination, so neither Dreyer nor Bigourdan had any reason to suspect that the object had already been discovered; hence the double listing.

Per Dreyer, NGC IC 1539 (= Bigourdan 359, 1860 RA 00 11 08, NPD 60 41) is "extremely faint, between two 13th-magnitude stars". The position precesses to RA 00 18 25.2, Dec +30 05 41, which is about 1.2 arcmin northeast of the galaxy, and not far from Mitchell's equally poor position (as discussed at NGC 70). However, the two 13th-magnitude stars flanking the galaxy, which were noted by both observers, confirm the identity of the two listings.