NGC 523 (UGC 979, Arp 158) Galaxy in Andromeda

Located at: RA 01 hours 25 minutes 20 seconds, Dec +34 degrees 01 minutes 28 seconds

Size: 2.8' x 0.8' Magnitude: 13.5 blue Class: Pec

North is up

West to the right


 14.5" f5 Newtonian reflector


  ST-8XME, self-guided, binned 1x1, temp -15c, camera control MaxIm DL 4.56


Lumicon Red filter, 640 minutes (64 x 10 minute subs), 10/27/28/2017; seeing 2.3-4.8 FWHM per CCDStack

Processing: CCDStack 2.94.6355.18107, Photoshop CS5.1

 Rolling Roof Observatory, Thousand Oaks, CA 91360 (+34d 13m 29s -118h 52m 20s)

Notes: This is another small Arp galaxy in Andromeda that I am imaging at the end this month ... see the NGC 70 group ...

From the NGC / IC Project:

NGC 523 = Arp 158 = NGC 537 = UGC 979 = MCG +06-04-018 = CGCG 521-022 = IV Zw 45 = VV 783 = PGC 5268

01 25 20.8 +34 01 30

V = 12.7;  Size 2.5'x0.7';  Surf Br = 13.2;  PA = 108d


24" (11/24/14): fairly bright, moderately bright, very elongated 7:2 ~E-W, ~1.1'x0.3'.  This disrupted galaxy (or merger) appeared very asymmetric, widening a bit at the east end and tapering slightly to the west.  A small, relatively bright knot (HII complex or core of companion?), ~10" diameter, is at the east end.  An easily visible mag 14-14.5 star is embedded at the west end.  The main body, which extends ~40" from the knot to the star, is fairly thin and only very weakly brighter in the center.  With careful viewing, a very faint narrow plume extends west of the main glow.


13.1" (12/22/84): moderately bright, thin edge-on 4:1 ~E-W.  Located north of the NGC 483-517 cluster.


Heinrich d'Arrest found NGC 523 on 23 Aug 1862 and described this galaxy as a "Double Nebula, F, S, both very near.  A *11 precedes by 11.65 seconds."  As he noted this object as a "Nebula duplex", he apparently saw the knot at the east end (identified in NED as NGC 523 NED02).  WH probably discovered this galaxy earlier on 13 Sep 1784 (problematic sweep 271) and simply noted H III-170 = NGC 537 as "stellar".  His RA readings for objects in this sweep are poor (given to the nearest minute) and assuming H III-170 has an error of about 55 sec in RA, then NGC 523 = NGC 537.  The eastern knot was the site of SN 2001EN.