Sierra Buttes and Lassen 7/20 to 7/27 (Planetaries)

by Steve Gottlieb

Here are some planetaries from the week-long marathon session - Steve

NGC 6026
16 01 20.9 -34 32 39
V = 13.2; Size 54"x36"

18" (7/22/06): picked up unfiltered at 160x as a mag 13.5-14 star surrounded by a 40"x30" faint halo elongated SW-NE. A UHC filter increases the contrast so the disc appears fairly faint to moderately bright (easy with direct vision). 325x provided a good view unfiltered and the elongation appeared closer to WSW-ENE. The easy central star was visible steadily and the dimensions roughly 45"x35".
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NGC 6058
16 04 26.4 +40 40 59
V = 12.9; Size 24"x21"

18" (7/20/06): picked up at 115x as a mag 13-13.5 star surrounded by a small 20" halo. Adding an OIII filter the halo brightened significantly and increased slightly in size. Nice view at 225x as the central star and halo are both displayed prominently. At this magnification, the halo was slightly elongated NNW-SSE, roughly 25"x20" in size. At 325x, the planetary was beautifully framed within an isosceles triangle which just fits within the high power field of view. Adding a UHC filter the halo was irregular in surface brightness and dimmed around the periphery, perhaps extending to 30".
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IC 4593
16 11 44.5 +12 04 17
V = 10.8; Size 13"x10"

18" (7/20/06): at 160x the 11th magnitude central star is encased by a small, oval halo, elongated NNW-SSE, ~10"x7". The planetary has the characteristic blue glow seen in this class of objects. Good response to OIII blinking at this power. The central star is more prominent at 225x and 325x but there was no additional details visible in fairly poor seeing.
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NGC 6072
16 12 58.1 -36 13 48
V = 11.3; Size 70"

18" (7/22/06): viewed unfiltered at 225x, 325x and 435x as a moderately bright, round, 1' disc of irregular surface brightness. The disc appears mottled with slightly darker and brighter regions though I couldn't say there was a definite annularity. Inside the rim there appeared to be a darker zone or darker patches that did not extend, though, all the way to the center. In fact, the very center appeared to brighten very slightly.
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Abell 39
16 27 33.6 +27 54 34
V = 12.9; Size 170"

18" (7/20/06): visible unfiltered at 115x as a large, low surface brightness, roundish glow 2'-3' in diameter. Adding an OIII filter gives more definition and structure though the contrast gain is not dramatic. A thick rim is slightly brighter, though not uniform around, giving a weak annular appearance with an ill-defined slightly darker center.
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NGC 6210
16 44 29.4 +23 48 00
V = 8.8; Size 20"x13"

18" (7/20/06): appears as a beautiful light blue cosmic egg at 225x with an extremely high surface brightness. Appears slightly elongated ~E-W, ~25"x20" with a very faint thin outer envelope. At 325x and 435x the faint outer halo is obvious, increasing the size ~35"x28" with the elongation possibly WSW-ENE. Viewed in fairly poor seeing on 7/20 but on 7/22 in good seeing I was able to use as much as 807x. In these conditions and magnification, the surface brightness was irregular and the faint outer shell fairly prominent. The bright inner disc was oval but not symmetric.
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IC 4634
17 01 33.6 -21 49 34
V = 10.9; Size 11"x9"

18" (7/22/06): picked up at 225x as a bright, small, blue disc of very high surface brightness. Good contrast gain using the UHC filter. Appears much brighter than the similar mag 11 star using the filter. At 435x, the planetary is slightly elongated N-S, ~10"x8" with strong flash of a central star. There appears to be a much fainter, very thin envelope encasing the high surface brightness disc. Similar view at 565x though the elongation was clearer and the outer envelope increased in size to ~15"x11".
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Minkowski 2-9 = Minkowski's Butterfly
17 05 37.9 -10 08 34
V = 14.6; Size 39"x15"

18" (7/22/06): viewed unfiltered at 435x. Two thin jets oriented N-S extend from the faint mag 14.5 central star. In moments of sharp seeing, the jets appear weaker or detached from the star. A brightening at the tip of the northern extension was intermittently glimpsed.
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NGC 6302 = Bug Nebula
17 13 44.6 -37 06 12
V = 9.7; Size 83"x24"

18" (7/22/06): fascinating view unfiltered at 325x. In the center is a very high surface brightness "core" of only 10"-12" in diameter that brightens slightly to the center and is encased in a larger, fainter envelope. Extending from the central core are two remarkable wings oriented WSW-ENE. The following wing is much shorter but slightly brighter and this extension abruptly shoots towards the SE near the end. The much longer preceding wing heads WSW and is cut by a darker lane that detaches the western tip.
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NGC 6309 = Box Nebula
17 14 04.2 -12 54 39
V = 11.5; Size 52"

18" (7/22/06): superb view at 807x! This bipolar elongated planetary appears pear-shaped with the brighter, larger lobe on the NNW and a smaller, slightly fainter nodule on the SSE end. The nebulosity dims between the lobes but there appears to be a very small bridge of faint haze bridging the knots.
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NGC 6369 = Little Ghost Nebula
17 29 20.4 -23 45 35
V = 11.5; Size 30"

18" (7/22/06): beautiful view at 435x. The 30" annular ring is brightest along a "C" shaped section from NE moving clockwise to the SW and locally brighter at the NW end. The central hole is round, well-defined and relatively large compared to the rim.
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NGC 6439
17 48 19.8 -16 28 44
V = 12.7; Size 6"x5"

18" (7/25/06): easily picked up at 115x as a quasi-stellar light-blue mag 12.5 "star" just 1' S of a mag 10.4 star. Very good response to the OIII filter. A very small disc was visible at 225x, perhaps 3" in size. Adding a UHC filter this compact planetary was similar in brightness to the mag 10.4 star and appeared to increase slightly in diameter. At 435x a small oval, ~4"x3" was resolved of uniform surface brightness except it seemed to fade around the periphery, hinting at a thin faint envelope. Located in the NW corner of Sgr near the border of Ophiuchus and Serpens Cauda.
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NGC 6445
17 49 15.3 -20 00 34
V = 10.9; Size 38"x29"; Surf Br = 9.9

18" (7/22/06): this fascinating planetary was viewed at 435x. The overal shape is rectangular with the two longer sides oriented NW to SE. Both ends are noticeably brighter giving an annular appearance. The NW end is slightly brighter and irregular in surface brightness with a brighter spot or two. The rim of the NW end is slightly bowed out and has a well-defined boundary edge in the interior. The rim at the SE end of the planetary is unusually straight and well-defined and with averted vision it appeared to extend slightly beyond the main body of the planetary. The bright lobe at this end is bar-shaped and extended SW to NE, in the direction of the minor axis.
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Minkowski 4-9 = PK 24+5.1 = PN G024.2+05.9
18 14 18.5 -04 59 23
V = 14.1; Size 46"x38"

18" (7/20/06): picked up unfiltered at 115x as a faint, ill-defined glow ~35" in diameter. The view is improved at 325x and the planetary appears slightly elongated NNW-SSE, perhaps 40"x35" with an ill-defined halo and an irregular surface brightness. A mag 15 star is just off the NW end and a mag 15.5 star is right at the east edge. The contrast improves somewhat adding a UHC filter and the halo's periphery sharpens up.
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Vorontsov-Velyaminov 3-4
18 30 37.9 -19 15 20
Size Stellar

18" (7/25/06): at 325x I found a faint, very close double "star" oriented SW-NE with components between mag 14-15. The southern component did not respond to a UHC filter though it did appear distinctly quasi-stellar, perhaps 2"-3" in size. The observation was confused, though, by the nearby star. Still, the non-stellar nature was definite. This observation appears to agree with one from 9/3/05.
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Abell 46
18 31 18.9 +26 56 17
V = 13.8; Size 63"x60"

18" (7/22/06): at 160x and OIII filter, a well defined faint disc, ~1' in diameter, was visible continuously with averted once it was identified. It appeared slightly elongated or irregularly round. At 260x, without a filter, the faint 15th magnitude central star was visible continuously.
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Vy 1-4 = PK 27-3.2 = PN G027.4-03.5
18 54 01.9 -06 26 20
V = 13.6; Size <10"

18" (7/22/06): Picked up at 160x as the southern component of a double star with the brighter component to the north. Excellent contrast gain with the OIII filter and the planetary appears significantly brighter than this star using the filter. Even at 160x the planetary has a soft appearance and is clearly quasi-stellar. At 435x it appeared distinctly non-stellar with a disc diameter of ~4".
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Kohoutek 4-8
18 54 20.0 -08 47 33
V = 14.2; Size Stellar

18" (7/22/06): easily blinked at 160x using a UHC filter. Without a filter appears as a mag 14.5 "star" within a shallow arc of 4 stars located just 5' WNW of the beautiful planetary IC 1295. The planetary is furthest north of the 4 stars in the short arc and responds well to blinking. Both planetaries as well as globular N6712 are visible in the same low power field of view.
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IC 1295
18 54 36.5 -08 49 49
V = 12.5; Size 102"x87"

18" (7/22/06): at 220x and UHC filter this fairly bright, large planetary was crisp-edged, slightly elongated ~E-W, ~1.5x1.3' in size. The rim appeared slightly brighter, particularly along the south side giving a weak impression of annularity. Several stars bracket the planetary and 4 or 5 mag 14-15.5 stars appear within the disc at 325x without a filter. I viewed this object along with N6712 and the stellar planetary K 4-8 in the same low power field of view!!
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NGC 6818 = Little Gem Nebula
19 43 57.7 -14 09 11
V = 9.4; Size 22"x15"

18" (7/23/06): this very high surface brightness blue planetary takes high magnification well and 565x provided an excellent view. Appears slightly elongated N-S, ~20"x15". Most striking is an annular structure with a brighter rim and darker center. The rim has an irregular surface brightness and is brighter along the south and east side. Although the contrast of rim and darker center is fairly low, the relative thickness of the rim is comparable to M57. Barnard's Galaxy lies just 40' S.
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