Arp 309

ARP 309 2016 Nov 25

Object: ARP 309  (NGC 942 & 943) Date:   2016 November 25
Peculiarity:    Double galaxies.
Constellation:           Cetus Time & altitude:  23.00 UT     26º
Catalogue data: Seeing (5 high):                               3/5
            R.A:                2h 29m Transparency (5 high):           2 to 3/5
            Dec:                -10º 50 Telescope:     0.5m f4.1 Dob.
            Magnitudes:   14.9 & 14.0 Eyepiece:      8mm Ethos      x260
Galaxy sizes (mins): both 0.4 x 0.3 Filters:            Lumicon Deep Sky


I observed these galaxies just W of the meridian in my site’s darkest southern sky. However the eyepiece was at an awkward, uncomfortable height.  There is an asterism of five stars Np in the same field of view but off the drawing. The brightest star is 9.3m. The asterism is useful in keeping track of the correct field.

Megastar 5 gives magnitudes of 12.4 & 12.2. I judge 14th mag is more likely. This pair was visible with DV part of the time. The appearance was of a parallelogram with well defined edges. I could not separate the two galaxies. The filter darkened the sky background but did not make the galaxies any more visible.

No sign of 15th magnitude IC 230 which precedes this pair, in the same field of view.