Last Saturday night (10/13/01) we had quite a continent of observers up at Lake Sonoma, between Cloverdale and Healdsburg in the Sonoma County wine vineyards. Transparency and seeing were mediocre for the site -- down a half magnitude to approximately 6.0 with a few clouds drifting in from the west. But the relative humidity was low, winds nonexistent and the temperture warm enough all evening that I observing in T-shirt and shorts.
I started off the evening revisiting a few interesting planetaries. The far northern PN IC 1454 was discovered in the early 1890's by W.F. Denning with a 10" reflector, but was relisted as Abell as a "new" planetary 60 years later based on inspection of the original Palomar Sky Survey. The "Blue Snowball", NGC 7662, has an unusually high surface brightness and easily takes high power (500x in the case of this observation). My first view of NGC 7139 was 20 years ago with a C-8 and it was a tough object with that aperture!
NGC 7139 = PK 104+7.1 = PN G104.1+07.9
21 46 08.6 +63 47 29
V = 13.4; Size 86"x70"
17/5" (10/13/01): easily picked up sweeping at 100x without a filter. Appears moderately bright, round, 1.2' diameter, crisp-edged. A mag 13.5 star is off the SE edge. Excellent view at 280x without filter. The surface brightness appears irregular with a slightly brighter rim, particularly along the eastern half of the rim. An extremely faint star is intermittently visible right at the NE edge. A nice, elongated group of 6-8 stars follows the planetary in the same high power field. Central star not seen at 280x.
IC 1454 = PK 117+18.1 = Abell 81 = PN G117.5+18.9
22 42 25.0 +80 26 32
V = 14.4; Size 34"x31"
17.5" (10/13/01): picked up at 100x without filter as a faint, small disc wiutated 4' WNW of a mag 7 star. Excellent contrast gain with an OIII filter and appears as a round, 25" crisp-edged disc. At 220x without filter a faint mag 14/15 pair is at the NE edge. Very nice view using a UHC filter at 140x-220x; the PN is slightly elongated ~E-W but no other details are visible.
NGC 7662 = PK 106-17.1 = PN G106.5-17.6 = Blue Snowball
23 25 53.9 +42 32 05
V = 8.3; Size 32"x28"
17.5" (10/13/01): at 500x, this blue high surface brightness planetary has a beautiful double-shell structure with a small, dark center. The bright inner structure has a a delicate, embedded thinner ring of very high surface brightness which is weaker at the following end. In the center of this ring is a small, darker hole. The fainter, outer envelope is elongated SW-NE, ~35"x25", giving an asymmetric appearance with the outline of the inner ring.
Parsmamyan 2 is an unusual reflection nebula with illuminating star V633 Cas. When I did some researching on the object earlier this week I was surprised to find it catalogued as a Herbig-Haro object. These are small-scale highly collimated bipolar outflows from very young embryonic stars. This is just the third H-H object I've viewed.
Parsamyan 2 = HH 164 = V633 Cas
00 11 26.1 +58 49 29
17.5": this small, reflection nebula (and Herbig-Haro object) appeared as a fuzzy mag 13.5 "star" (GSC 3664-1546), easily identified at 220x. The star appears to be encased in a faint halo although difficult to confirm with certainty in fairly poor seeing. Located 26' SE of Caph (Beta Cass).
Another interesting object was Vorontsov-Velyaminov 790a (catalogue of interacting galaxies), which is referred to as the "Teardrop" galaxy in NED. On deep images, this galaxy appears to belong to a rare category of "collisional ring" galaxies (the "Cartwheel" galaxy is perhaps the best example). Although this detail was much too faint to be seen visually, it was neat to just pick up the galaxy --
MCG +03-05-013 = CGCG 460-020 = Mrk 360 = III Zw 33 = VV 790a = A0141+16 =
NPM1G +16.0051 = Teardrop Galaxy
01 43 56.5 +17 03 44
V = 14.4; Size 0.4x0.4; SB = 12.5
17.5": faint, very small, round, 15"-20" diameter, low even surface brightness. Located 1.8' ENE of a mag 13 star. Situated 25' SSW of UGC 1219
NGC 6956/UGC 11620/UGC 11623 are a close trio of galaxies in Delphinus in the same high power field which I had observed a couple of times previously but definitely worth revisiting --
N6956 = U11619 = MCG +02-53-001
20 43 53.7 +12 30 43
V = 12.3; Size 1.9x1.9; SB = 13.6
17.5": this moderately bright glow appears unusual as a mag 10.5 star is attached at the east side and interferes with viewing. The surface brightness of this barred spiral is pretty uniform except for a faint stellar nucleus. A mag 14 companion star (double) follows the brighter star. Brightest in a trio with UGC 11620 and 11623 to 7' SSE and 8' ESE, respectively.
UGC 11620 = MCG +02-53-002
20 44 09.8 +12 25 05
V = 13.6; Size 0.6x0.4; SB = 12.0; PA = 25d
17.5": faint, very small, elongated 4:3 SSW-NNE, 20"x15", slightly brighter core. A mag 13 star with a close, much fainter companion is 30" SE of center. Second brightest in N6956 (7' NNW) trio with U11623.
UGC 11623 = MCG +02-53-003
20 44 26.7 +12 29 51
V = 13.9; Size 1.0x0.7; SB = 13.5; PA = 40d
17.5": very faint, very small, roundish (probably viewed brighter core only). Follows a trio of mag 13-14.5 stars. Faintest of trio with N6956 and U11620.
UGC 12545 and 12546, a very close pair of 15th magnitude galaxies took quite a bit of effort to clearly resolve --
UGC 12545 = MCG +04-55-009 = CGCG 476-020
23 21 41.9 +27 04 14
V = 14.4; Size 1.2x0.5; SB = 13.7; PA = 85d
17.5": UGC 12545 and 12546 form a very close 1' pair of challenging, elongated galaxies. They require averted vision and are a bit too faint to hold simultaneously. U12545 is elongated 2:1 E-W, 30"x15". U12546 is just 1.0' N of center. This pair is located 23' SE of N7624. A third nearby edge-on, U12543 to the NW was not seen.
UGC 12546 = MCG +04-55-008 = CGCG 476-021
23 21 41.2 +27 05 14
V = 14.4; Size 1.3x0.3; SB = 13.3; PA = 19d
17.5": extremely faint, small, very elongated SSW-NNE, ~30"x10". Forms a very close, challenging pair with U12545 1' S. Both galaxies require averted vision and are a bit too faint to hold simultaneously. Located 23' SE of N7624.
UGC 12064 in Lacerta is very close triple system which I was hoping to resolve, but the seeing and transparency limited me to two members --
UGC 12064 = MCG +06-49-029 = CGCG 514-050 = 3C 449
22 31 20.6 +39 21 30
V = 13.6; Size 1.1x1.1; SB = 13.6
17.5": fairly faint, fairly small, slightly elongated N-S. A faint star (mag ~14.5) is close west [37" from center]. Forms the eastern vertex of a triangle with two mag 13 stars ~ 2' NW and 2' WSW. An extremely faint companion off the N side [0.6' N of center] was intermittently visible. This elliptical is the radio galaxy 3C 449. A second faint companion 1.6' WNW was not seen. UGC 12073 group lies 16' SE.
UGC 12064n = MCG +06-49-029n = CGCG 514-050n
22 31 21.3 +39 22 06
17.5": this close companion to UGC 12064 [0.6' N of center] was extremely faint and small, only intermittently visible with averted vision.
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