Arp 317

65 finalARP 317 2018 May 10

Object:   Arp 317 (Leo Triplet galaxy group) Date:               2018 May 10
Peculiarity:  Groups of galaxies.
Constellation:           Leo Time & altitude:        21.45 UT      46º
Catalogue data: (data is for NGC 3628) Seeing (5 high):                               3/5
            R.A:                11h 20m Transparency (5 high):                   3/5
            Dec:                13º 36 Telescope:     0.5m f4.1  Dob.
            Magnitude     10.3 Eyepiece       8mm Ethos                x260
            Galaxy size (mins)   15 x 3 Filters:            None


The triplet comprises M65, M66 (see Arp 16) and NGC 3637.

M65 (top): This is a 5:1 oval with the major axis aligned NS. There is a prominent round core and hints of dark structures adjacent to the core on its S side.  The W side of the galaxy is brighter than the E.

NGC 3628 (bottom):  This is a 3:1 oval with the major axis aligned EW. There is very little concentration towards the middle and no core. A  dust lane runs the length of the galaxy and is not at all easy to see. The part of the galaxy to the S of the dust lane is a very faint, subtle feature, also not easy to see. A star on the edge of visibility is on the SE edge of the halo.