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RA: 12h 10m 32.73s
Dec: +39° 24′ 19.6″
Con: Canes Venatici
Ch: MSA:612, U2:74, SA:7
Type: galaxy (Seyfert 1), Sa
Mag: B=11.2, V=11.9
Size: 6.025′ x 4.786′
Synonyms: H I-165
Burnham calls it a 11.2 mag barred spiral galaxy in Canes Venatici, measuring 2.5' x 1.6', which is very bright, small, elongated, very suddenly much brighter in the middle, bright nucleus.
Photo Index by Jim Lucyk: Sky&Tel. 4/84 p308, Astronomy mag. 6/78 p18, Astronomy mag. 7/77 p14, Astronomy mag. 7/86 p73, Astronomy mag. 9/78 p10, Sky&Tel. 3/88 p292, 293, Universe Guide to Stars & Planets (Ridpath & Tirion) p285, Galaxies (Ferris,1982) p123.
The RNGC (Sulentic and Tifft 1973) notes that this is a 11.5 mag galaxy. Their coded description reads EL,BNUC&ENDS.
G. de Vaucouleurs ("Galaxies and the Universe", Chapter 14 - Nearby Groups of Galaxies) notes that the five brightest members of the Ursa Major I (Z) group are NGC 4151, NGC 3941, NGC 4145, NGC 4369 & NGC 3813.
This galaxy is listed in the "Third Reference Catalogue of Bright Galaxies" as being a bright Seyfert galaxy. The integrated B magnitude of the stellar system (excluding the nucleus) = 11.28, and the B magnitude of the quasi-stellar nucleus = 12.4-13.4.
A comparison star chart for this galaxy with a variable nucleus appeared in Sky&Telescope, May 1978, p372. A 24' wide chart with 7 comparison stars is given, listing V, B-V and U-B values.
Hamilton, D., Keel, W. & Nixon, J.F. (1978) Variable galactic nuclei. Sky&Telescope, May, 72.
Tom Lorenzin, in the electronic version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "11.2M; 4' x 3' extent; very bright nucleus; appears as nebulosity surrounding 11M star; !good supernova prospect! very faint SP GAL N4156 (13M; 1' diameter) is a few minutes to NE; faint SP GAL N4145 is 30' to N and a little W."
POSS: pa130. m13 * 1'.3 NNW; m12 * 2'.3 N/sl W; m14.5 * 1'.4 WSW. -56 5'.1 NE.
UGC: no pa.
T&B: first * N: V=14.8; second *: V=11.5; * WSW not meas, but evidently fntr than 14.8.
15cm - like a * w/vf halo.
25cm - prob a m11.5 * on NE inv w/gx while gx itself has unconcen halo 1' diam. [you blind, Skiff!]
30cm - vwell concen to br m12 *ar nuc. concen pretty even (az). 2'x1' in pa120. nuc *ar at all magnifications. *s: m13.5 *s N & W @ 1'.25; m12 * (sim to gx) 2' N. -56 vis NE.
Observing site: Pinnacles overlook
[12h 10m 30s, 39° 24m 0s] An obvious Seyfert, with a bright, starlike nucleus. NGC 4156 is just NE of 4151.
The Messier objects
The Bennett objects
The Caldwell list
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