Lake Sonoma 6/17/06

by Steve Gottlieb

Although we're nearly at the summer solstice and the spring constellations are sliding down in the western sky, I took a look at a few of the spring favorites that came up in the recent thread on TAC. For more observing notes on these objects and 6500 additional NGC's, see http://www.ngcic.org/gottlieb/default.htm Steve Gottlieb

Hickson 61 (NGC 4169/4173/4174/4175

NGC 4169 is the brightest member of HCG 61 = "The Box". Appears moderately bright, fairly small, elongated 3:2 NNW-SSE, 1.2'x0.7'. Well concentrated with a 25" bright core that increases to the center. NGC 4174 is the smallest member of the striking HCG 61 quartet. It appeared fairly faint, fairly small, elongated 3:1 SW- NE, 0.9'x0.3', sharply concentrated with a bright 15"-20" rounder core with the extentions much fainter. NGC 4173 is the faintest member of the quartet. At 220x it appeared fairly large, very elongated 4:1 NW-SE, 1.5'x0.4'. Overall, low surface brightness with a very weak central brightening. NGC 4175 is the second of two edge- ons in the group. It appeared fairly faint, moderately large, elongated 5:1 NW-SE, 1.3'x0.25', broad weak concentration to a slightly brighter bulging core and fades at the tips.

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NGC 4216
12 15 54.2 +13 08 59
V = 10.0; Size 8.1x1.8; Surf Br = 12.8; PA = 19d

18" (6/17/06): very bright, very large, extremely thin edge-on 8:1 SSW-NNE, 7'x0.9'. Sharply concentrated with a striking high surface brightness core ~0.9'x0.3' that dominates the extensions with a mag 14 star just following the core. A dust lane appears to run along the eastern edge of the galaxy, mostly evident by a sharp light cut off along this edge. Brightest of three edge-ons in the field with N4206 and N4222.

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NGC 5474
14 05 01.2 +53 39 44
V = 10.8; Size 4.8x4.3; Surf Br = 13.9

18" (6/17/06): fairly bright, large, with an irregular asymmetric appearance. Broadly concentrated to a 1' brighter core that resides on the north edge of the galaxy. The 2.5' halo is slightly elongated N-S and spreads out from the core only towards the south! The halo has a slightly mottled texture and fades at the periphery. With averted vision the size increases to nearly 3'. A mag 13.5-14 star is just north of the offset core. A mag 13 pair at 14" lies 9' ESE. This disturbed galaxy is a member of the M101 group and the asymmetry is caused by tidal deformation by M101!

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NGC 5746
14 44 55.8 +01 57 19
V = 10.3; Size 7.4x1.3; Surf Br = 12.6; PA = 170d

18" (6/17/06): superb edge-on 7:1 N-S, ~6'x0.8', broadly concentrated to a 2'x0.7' elongated, bulging core. The core is mottled and clumpy due to a dust lane that appears to pass along the east edge of the core. The southern extension passes through a star and is slightly brighter and possibly longer though the northern extension extends as far with careful viewing (slightly lower surface brightness).

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NGC 5907
15 15 53.3 +56 19 44
V = 10.3; Size 12.6x1.4; Surf Br = 13.3; PA = 155d

18" (6/17/06): extremely large edge-on, roughly 12:1 NNW-SSE, ~10'x0.8', broadly concentrated to a brighter core but with no discernable nucleus. The 2' central core region is mottled with a couple of brighter spots and the extensions are also irregular in surface brightness. There appears to be a dust lane running along the western edge of the galaxy. A mag 14 star is just preceding the core.

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NGC 5981
15 37 53.3 +59 23 29
V = 13.0; Size 2.8x0.5; Surf Br = 13.1; PA = 140d

18" (6/17/06): fairly faint, fairly large thin edge-on 5:1 NW-SE, 1.5'x0.3'. Broad weak concentration though no well-defined core. First of a striking trio with N5982 and N5985.

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NGC 5982
15 38 39.8 +59 21 21
V = 11.1; Size 2.6x1.9; Surf Br = 12.9; PA = 110d

18" (6/17/06): fairly bright, moderately large, slightly elongated, sharply concentrated with a high surface brightness core increasing to a stellar nucleus. The halo is much fainter and increases in size to ~1.5'x1.2'. Second of an excellent trio in a string with N5981 and N5985.

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NGC 5985
15 39 37.0 +59 19 55
V = 11.1; Size 5.5x3.0; Surf Br = 14.0; PA = 13d

18" (6/17/06): fairly bright, large, elongated 3:2 ~N-S, the halo extends to ~4'x2.5'. Broadly concentrated to a brighter 40" core that increases slightly to the center. The halo is mottled and patchy giving a strong impression of spiral structure. This is largest and brightest overall of an excellent trio with N5981 and N5982.

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