Here is a very long – 19 hour – exposure of the Grus Triplet. From top to bottom – NGC7582, 7590 and 7599. The galaxies appear to be headed toward a final encounter somewhere toward the center of the group. However, I cannot detect any signs of interaction yet, despite the added detail with this very long exposure.

PlaneWave 12.5″ Astrograph with an ST11000 camera, Astrodon filters, and ASA gearless DDM-85 mount. F/8 LRGB (90/8mn L, 16/8min each 2×2 RGB).