Arp 41

ARP 41 2017 Jan 2

Object:  ARP 41  (NGC 1232) Date:        2017 January 2
Peculiarity:    Spiral: low-surface brightness component on arm.
Constellation:           Eridanus Time & altitude:   20.45 UT             18º
Catalogue data: Seeing (5 high):                               3/5
            R.A:                3h 10m Transparency (5 high):                 4/5
            Dec:                -20º 35 Telescope:     0.5m f4.1 Dob.
            Magnitude:    10.1 Eyepiece:      8mm Ethos      x260
            Galaxy size (mins): 7 x 6 Filters:            None


A disappointing view due to the high S declination and resulting low altitude even near culmination. The faintest star recorded in my drawing is 15.2m per Megastar, showing the conditions were good. Arp 41 was seen with DV but only the central region of this face-on spiral could be picked out. There was no trace of the outer halo.  The ‘component on arm’ is NGC 1232A magnitude 15.2, so probably out of range.

Sky & Telescope contributor Sue French writes (2017 January page 55) “Viewed with the 10-inch scope at 220x the galaxy’s unevenly bright countenance indicates spiral arms unfolding counter-clockwise.” So, much more detail with half the aperture. Sue tells me she observes from upstate New York where Arp 41 transits at 27º.