400/500mm - 17.5" (6/14/96): HCG 78a appears very faint, fairly small, very elongated 3:1 E-W, 1.0'x0.3', even surface brightness. Forms a close double with HCG 78b 1.2' SW.

900/1200mm - 48" (5/9/18): at 375x and 488x; fairly bright, moderately large, edge-on 5:1 E-W, ~50"x10", very small brighter nucleus. UGC 10057 is the largest member of HCG 78 but it has a lower surface brightness than CGCG 319-024 = HCG 78B 1.2' SW. HCG 78D is 1.8' NE and 78C lies 2.8' SE. The nearest stars are a mag 15.4 situated 1.3' NNE and a mag 12.9 2.6' SE (near HCG 78C).