This is ARP 243 – two galaxies caught in the late stages of a merger. Note the luminous blue in the tidal tails, which are active with new star formation.

ARP 243 lies about 25 million ly away in Cancer.

PlaneWave 12.5″ Astrograph with ZWO ASI6200 camera, Astrodon filters, and ASA DDM-85 mount. F/8 LRGB (73/8min L, 16/8min each 2×2 RGB).