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Type: galaxy, S0
Mag: B=12.9, V=?
Size: 2.398′ x 1.778′
PA: 145°
Synonyms: H II-148, H II-020
William Herschel discovered it on 23 January 1784 with an 18.7-inch f/13 speculum telescope. He called it "vS." It received the designation H II-20. On the night of 13 April 1784 he observed a nebula H II-148, which he described as "not faint, round, vgbM." Dreyer notes that II-20 is "quite certainly the same as II-148. There is a sketch of it under date Jan. 23 1784 (Sweep 105), which agrees perfectly with the description of II-148 in Sweep 498, Dec. 28, 1785: 'preceding a row of pretty considerably stars and near the most south of them, making a rectangle' (ie. a right angle). Also in Sweep 560, May 1, 1786, II-20 is said to be 'preceding the most s. of a row of stars.'
The RNGC (Sulentic and Tifft 1973) notes that this is a 12.5 mag galaxy. Their coded description reads E,R,BM,*1'FO.
This galaxy appears on page 42 of "The Hubble Atlas of Galaxies" by Allan Sandage (1961, Washington, DC).
Photo Index by Jim Lucyk: Hubble Atl.of Gal. (Sandage 1961) p42.
Tom Lorenzin, in the e-version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "13M; 1' diameter; small, round and bright; 9M star 45" to NE; see photo at HAG-42; can be found at the end of a 10' long chain of 7-8-9M stars, the N-most of which is a neat little 10" pair; twice the distance of the star chain's length, and in the direction that it leads away from N4612 lies EL GAL N4623 (13.3M; 2'x 0.5' extent), a soft, N-S-oriented slash with a 14M stellar core; it's about 20' N and a bit E of N4612."
Lacaille's catalogue
The Messier objects
Dunlop's catalogue
The Bennett objects
The Caldwell list
Named DSOs
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