Short IHOP on 5/12/07 and Lake Sonoma on 5/14/07

by Steve Gottlieb


Last Saturday (5/12) I drove out to the Ice House Observation Plateau (IHOP, for short) and met up with a few of the Sacramento area observers (Marsha, Shneor and Jim) at their 5000+ ft site in the Sierras. After a day's rest, I ventured north on 101 to the Sonoma wine country after teaching and spent several hours observing at Lake Sonoma with Bob Douglas. It was quite chilly on Saturday night at IHOP, but seeing was good, skies were clear and there is an endless supply of galaxies to view this time of year in my 18-inch Starmaster. On the other hand, conditions at Lake Sonoma were quite mild and I only needed a jacket around midnight. But low clouds and moisture in the south were reflecting quite a bit of light from Santa Rosa, so I mostly stuck to galaxies higher in the sky on Monday night.

I've been working on completing the NGC -- at least as many of the 7840 entries that are viewable from our latitude (that's roughly 6500) and have whittled that list down to just 135 objects after tracking down a couple of dozen faint spring galaxies. I also took some time at IHOP and Lake Sonoma to look at some favorite eye candy with my 18-inch Starmaster. So, here's some of the bright stuff first ...

NGC 3489
11 00 18.6 +13 54 04
V = 10.3; Size 3.5x2.0; Surf Br = 12.3; PA = 70d

18" (5/14/07): very bright, large, elongated 2:1 WSW-ENE, 2.5'x1.25'. Sharply concentrated with a round, intense core (relatively small) highlighted by a very bright quasi-stellar nucleus. A mag 12.5 star lies 1.5' WSW of center, just outside the halo.
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NGC 3521
11 05 49.2 -00 02 02
V = 09.0; Size 11.0x5.1; Surf Br = 13.2; PA = 163d

18" (5/14/07): very bright spiral with impressive structure, elongated at least 5:2 NNW-SSE, ~7.5'x3'. Contains a bright, elongated core highlighted by an intense, stellar nucleus. The halo is noticeably mottled at first glance and a dust lane runs NNW-SSE along the west side of the core. There is a strong impression of spiral structure with an arm attached on the east side that extends to the north and appears to curve towards the west in the outer halo. The halo appears more extensive or slightly brighter on the northern end. A more difficult arm appears to sweep to the south on the west side of the core.
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M108
11 11 31.8 +55 40 14
V = 10.0; Size 8.7x2.2; Surf Br = 13.1; PA = 80d

18" (5/14/07): very bright, very large, elongated 4:1 WSW-ENE, ~8'x2'. This striking galaxy has a very mottled, patchy appearance with the main body appearing twisted or distorted. A few brighter patches or knots are visible along the major axis with a prominent knot along the west side. The core region is streaked with dust. The brightest portions of the two extensions have slightly different orientations or central axes! The galaxy bulges out a bit on the east end and the galaxy appears to bend a bit towards the north on the west end adding to the asymmetry. A couple of faint stars are superimposed on the eastern extension and close to the center is a prominent mag 12.5 star masquerading as a bright, stellar nucleus. The Owl Nebula, M97, lies 48' SE.
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M109
11 57 35.9 +53 22 29
V = 9.8; Size 7.6x4.7; Surf Br = 13.6; PA = 68d

18" (5/14/07): bright, large, elongated 3:2 or 5:3 SW-NE, ~6.5'x4'. The galaxy lies between a mag 9.5 star 5' SW and a mag 12 star 3.4' NE of center just beyond the edge of the halo. Sharply concentrated with a fainter halo and a bright, oval core that increases slightly to a faint, stellar nlucleus. With averted vision, the halo is quite extensive and extends to the mag 12 star to the NE. The halo appears mottled or dusty with an impression of spiral structure. A mag 12.5 star is superimposed less than 1' N of the center and another mag 12 star is near the the SW end. Located 5' NE of a mag 9 star and 39' SE of mag 2.4 Gamma UMa.
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NGC 4111 = UGC 07103 = MCG +07-25-026 = CGCG 215-028 = PGC 38440
12 07 02.6 +43 04 01
V = 10.7; Size 4.6x1.0; Surf Br = 12.2; PA = 150d

18" (5/14/07): this striking edge-on is extends 6:1 NNW-SSE, ~3.5'x0.6'. Dominated by a small, sharply concentrated, intense core. The core is only 24"x15" and brightens somewhat to the center. The eastern flank possibly has a sharper edge, but no dust lane was visible. Located 4' SW of a wide double star (8.2/10.7 at 34")
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NGC 4449
12 28 11.2 +44 05 36
V = 09.6; Size 6.2x4.4; Surf Br = 13.0; PA = 45d

18" (5/14/07): very mottled, irregular appearance, elongated ~2:1 SW- NE, ~5'x2.5'. The core is quite splotchy in appearance with a couple of bright knots, the most prominent is attached to the southwest of the core. The main body is roughly rectangular with an extension at the NW "corner" that ends with a bright knot or knots. Another extension or knot is off the NE corner. A mag 13 star lies 2.4' E of the core and 1 or 2 additional very faint stars or knots are superimposed in the central region.

18" (5/8/04): fascinating view of this "Magellanic" system at 323x! The galaxy is very irregular in appearance and surface brightness with a large, bright, elongated core oriented SW-NE. The core appears offset to the south side of the galaxy.

Several knots (giant HII regions) are visible outside the core. The brightest is a well-defined obvious patch on the north edge of the galaxy, 1.5' from the center. This object is #15 in Hodge- Kennicutt's 1983 "Atlas of HII regions in 125 galaxies" and it is nearly comparable in surface brightness to the core. Roughly 1' SE is a smaller, faint knot that is collinear with [HK83] 15 and a mag 13.5 star 2.4' east of the core. A third difficult knot can sometimes be glimpsed about 40" SW of [HK83] 15. Finally, attached on the south end of the core is a larger, bright knot, although initially I thought this was just part of the core.
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NGC 4605
12 39 59.4 +61 36 33
V = 10.3; Size 5.8x2.2; Surf Br = 12.9; PA = 125d

18" (5/14/07): very bright, large, nearly edge-on 3:1 NW-SE. The relatively large, bulging core is mottled. The SE extension is brighter, mottled (HII regions) and tapers towards the tip. The very tip of this extension appears to hook slightly towards the east. The fainter NW extension is much more diffuse, is broader and fades at the ends. The major axis of the two extensions are slightly skewed with respect to each other as if they were bent at the center or possibly the brighter SE extension is warped or distorted.
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NGC 4656 = Hockey Stick
12 43 58.2 +32 10 13
V = 10.5; Size 15.1x3.0; Surf Br = 14.5; PA = 33d

18" (5/14/07): this fascinating galaxy forms one of the most striking pairs in the sky with N4631 32' NW. At 220x, the distorted shape extends ~9'x1.5' in a SW-NE orientation. On first glance, it appears the bulging core is offset at the SW end, though with averted vision a very low surface brightness broader extension continues to the the SW of the core for several arcminutes before fading into the background. The core is very bright and mottled with a bright knot (HII region) jutting out to the west at the southwest end of the core. The NE extension has a remarkable, fairly bright 2' extension (N4657), hooking to the east at a 45 angle from the major axis (the "blade" of the hockey stick). There is a small, faint, detached knot beyond the east end of the "blade" that appears to have broken off. The unusual bend and knot at the NE end is a result of a prior tidal interaction with its more massive neighbor, N4631. ************************************************************

NGC 4710
12 49 38.8 +15 09 55
V = 11.0; Size 4.9x1.2; Surf Br = 12.8; PA = 27d

18" (5/14/07): bright, fairly large edge-on, nearly 7:1 SS-NNE, ~3.5'x0.5' with tapered extensions. The core is small and round, ~25" in diameter. The galaxy is irregular in surface brightness and mottled with a brighter knot near the NNE tip. A dust lane appears to slash across the galaxy, nearly perpendicular to the major axis and crossing to the NE of the core. A mag 13 star lies 1.5' E of the core.
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NGC 4725
12 50 26.3 +25 30 03
V = 9.4; Size 10.7x7.6; Surf Br = 14.0; PA = 35d

18" (5/12/07): very impressive spiral structure visible. Two arms emerge from the very bright oval core. One arm is attached at the NE end of the core and sweeps to the north before hooking back to the west. Three faint stars are superimposed along this arm. A second broader arm is attached at the southwest end of the core. This arms heads south before hooking towards the east. Both arms have brighter patches near the ends of the major axis.
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NGC 5322
13 49 15.1 +60 11 26
V = 10.2; Size 5.9x3.9; Surf Br = 13.6; PA = 95d

18" (5/14/07): very bright, fairly large, oval, 2.5'x1.75'. Sharply concentrated with a very bright, 40" core that increases to the center. Two or three mag 14-15 stars are superimposed on the halo including one to the south and one to the east of the core.
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For a challenge object, I took at look at NGC 4486B, a dwarf companion to M87, located just 7' to the NE. Hubble images of this galaxy have revealed a double nucleus (reminiscent of M31's) suggesting a 500-million-solar-mass central black hole. I doubt this galaxy would be noticed at less than 200x as it is very tiny and I logged it as "fairly faint, very small, round, 15" diameter. Contains a bright, sharp stellar nucleus with a small halo."

I also spent some time with a very faint cluster of galaxies near Theta Crateris, whose brightest member is NGC 3732. The group includes NGC's 3723, 3732, 3730, 3722, 3724 along with 3 or 4 galaxies that are not found in any of the common galaxy catalogues. Unfortunately, because of poor discovery positions it's very difficult to sort out all of these catalogue numbers correctly as there are several extremely dim galaxies in this field that could apply.

The brightest galaxy in the area, NGC 3732, was described as "moderately bright, fairly small, elongated nearly 3:2 E-W, ~1.0'x0.7'. Contains a bright core which gradually increases to the center. A mag 12 star lies 1' SW. Brightest in a group with a string of three very faint galaxies 10'-12' NNE and an additional 4 very faint galaxies 5'-8' further north."

The string of three galaxies I mentioned 10' NNE includes NGC 3722, 3724 and MCG -01-30-008. But continuing a bit further north, there is another group of dim galaxies including NGC 3730, 2MASX J11344327-0931595, 2MASX J11343191-0932005 and 2MASX J11344333-0930305. These last galaxies required careful viewing, high power and good conditions in my 18-inch just to glimpse.

Another interesting group surrounded NGC 4556 in Coma which is located just 55' N of the gorgeous edge-on with dust lane, NGC 4565. But few observers probably use 4565 to hop off to view 15th-16th magnitude galaxies -- why take your eyes off NGC 4565! NGC 4556 was logged as "fairly faint, fairly small, slightly elongated E-W, 0.6'x0.5', bright core, very small brighter nucleus. A mag 14 star is just off the south side. "

This galaxy is the first in a group that includes NGC 4558, NGC 4563, IC 3556, IC 3559, IC 3561, IC 3585 and IC 3590. The IC galaxies were missed by the Herschel's and only discovered on early photographic plates by Max Wolf.

Both nights were very successful, though the transparency was notably down from the New Mexico skies (at Star Hill Inn) I observed in the previous month -- so, I'm looking forward to some darker nights this summer.

Steve


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