Arp 91

ARP 91 2015 Aug 8

Object:            ARP    91

(NGC 5953 & 5954)

Date:               2015 August 8


Peculiarity:    Spiral with large high surface brightness companion on arms.
Constellation:           Serpens Time & altitude: 21.50 UT     34º
Catalogue data: Seeing (5 high):                               4/5
            R.A:                15h 35m Transparency (5 high):                   4/5
            Dec:                +15º 12 Telescope:     0.5m f4.1 Dob.
            Magnitudes:    13.3 & 13.7 Eyepiece:      8mm Ethos      x260
   Galaxy sizes (mins):  1.6×1.3 & 1.3×0.6 Filters:            None.


A pair of galaxies seen in contact and aligned more or less EW. NGC 5953 precedes and is the more easily seen of the pair. It is round. NGC 5954 is elongated 5:2 in NE-SW.  Oddly, in Arp’s photo the elongation is NS so possibly I am seeing a hint of the tidally distorted arm that points to 5953. No structure seen in either galaxy. A 15.3m star preceding 5953 was not seen, I suspect due to low altitude and it not being quite the end of twilight.