Arp 257

Arp 257 2019 Feb 10

Object:   Arp 257 (UGC 4638 & companion) Date:               2019 February 10
Peculiarity:  Irregular clumps.
Constellation:           Hydra Time & altitude:        23.00 UT     36º
Catalogue data: Seeing (5 high):                               3/5
            R.A:                8h 52m Transparency (5 high):                   4/5
            Dec:                -2º 22 Telescope:     0.5m f4.1  Dob.
            Magnitude     15.0 (but see notes) Eyepiece       8mm Ethos                x260
            Galaxy size (mins)   2.7 x 2.1 Filters:            None


It is easy to find the location of Arp 257, there is a noticeable line of three equidistant 12th magnitude stars nearby. Observed near culmination.

Sources disagree about Arp 257’s magnitude. Megastar lists UGC 4638 as 14.8 and companion MCG+0-23-6 as 15.6. Kanipe/Webb state 15 & 17. That the main galaxy has a UGC designation implies it is no fainter than 14.5 (blue photographic).  In these viewing conditions a 14.5 galaxy should be easy to see. However, this object is desperately faint and difficult. Only after studying the field for 20 minutes did I glimpse a faint oval glow. I only saw this on and off using AV. There was no sign of the MCG companion.