William Herschel discovered NGC 7578 = H III-182 = h2225 on 18 Sep 1784 (sweep 277) and recorded "2 vS stars about 2 or 3' distance with excessively faint nebulosity between them. I saw also a third star." He probably resolved the pair, though his separation estimate is much too large. On 15 Oct 1784 (sweep 290), he logged "Suspected, E, 240 shewed 4 or 5 small stars with seeming nebulosity but left it doubtful." JH simply called this object "F" but his position matches - no mention of being double or nearby faint stars. The brighter northeast member is designated NGC 7578B in RC2, RC3, UGC, MCG and Hickson. See Corwin's notes for a full discussion.

400/500mm - 17.5" (9/7/96): fairly faint, small, round, 45" diameter. A mag 14 star is at the NE edge and a second mag 14 star 0.9' S. Forms a double system with UGC 12477 = HCG 94b on the SW side of the halo. The brighter cores of the galaxies are cleanly resolved but both appear to be encased in a common outer halo. The faintest member, HCG 94c, lies 2.2' NE. HCG 93 lies only 32' NW!

17.5" (9/23/89): this is the brightest member of the HCG 94 compact group in AGC 2572 (identified as NGC 7578B in RC2, UGC and HCG). Faint, small, slightly elongated SW-NE. Attached to fainter NGC 7578A = HCG 94b just 34" SW of center in a common halo. A mag 15 star is at the NE edge 15" from center and a mag 14 star is off the south side 52" from center.

600/800mm - 24" (8/14/15): at 375x; fairly faint to moderately bright, small, round, 24" diameter, very small bright nucleus. A mag 14.5 star is just off the northeast side [17" from center]. Forms a double system with NGC 7578A = HCG 94B just 34" SW. The companion appeared fairly faint, small, round, 20" diameter, contains a very small, bright nucleus. NGC 7578C = HCG 94D, just 27" NE, is the faintest of 4 in HCG 94 and appeared extremely faint and small, round, only 6" diameter, visible only part of the time. Finally HCG 94C lies 2.2' NE and appeared faint to fairly faint, small, elongated at least 3:2 N-S, contains a small brighter core and very faint extensions NNW-SSE, 18"x10". The quartet (along with the mentioned star) are in a 2.8' linear string oriented SW-NE.

24" (8/16/12): at 376x the brightest member of HCG 94 appeared moderately bright, very small, round, 25" diameter, fairly high surface brightness, very small bright nucleus. A mag 14.5 star is barely off the northeast end. Forms a close pair with HCG 94B (34" between centers) with HCG 94D only 24" NE (very close to the mag 14.5 star). HCG 94B NGC 7578A) appeared fairly faint, very small, round, 20" core surrounded by a very low surface brightness halo. HCG 94D NGC 7578C) appeared extremely faint and small, round, 6" diameter. HCG 94C lies 2.2' NE and appeared faint, small, elongated 2:1 ~N-S, contains a very small slightly brighter core and faint extensions NNW-SSE, ~20"x10". A mag 14 star lies 50" S.

900/1200mm - 48" (10/27/16): at 488x; bright, fairly small, round, sharply concentrated with a very bright core that gradually increases to the center and a low surface brightness ~30" halo. A mag 14.5 star is at the NE edge [17" from center]. Forms a bright double system with NGC 7578A = HCG 94B 0.6' SW. The companion appeared fairly bright, small, round, sharply concentrated with a very bright core increasing to small intense nucleus. HCG 94D, just northeast of the mag 14.5 star, is faint to fairly faint (V = 16.1), very small, round, 8" diameter, even surface brightness.

HCG 94C, the third brightest (V = 15.1) and perhaps the largest in the septet, is 2.2' NE. It appeared moderately bright and large, very elongated at least 3:1 NNW-SSE, ~30"x10", well concentrated with a sharp bright nucleus. HCG 94F, just 0.5' NW, is very faint (V = 17.0), very small, slightly elongated, 8"x6". HCG 94G, 0.9' N of HCG 94C, is an extremely small, very faint glow (V = 17.2), only 6" diameter. Completing the septet is HCG 94E, 1.2' NNE of NGC 7578. This extremely faint (V = 16.9) edge-on extends 0.4'x0.1' and has a very low even surface brightness. The observation was made through thin clouds. This septet lies at a distance of ~570 million light years.

Notes by Steve Gottlieb