OR 1: GSSP and Sierra Buttes 2007 (Planetaries)

by Steve Gottlieb

After 4 superb nights at Lassen (3 at the Bumpass Hell lot and 1 at Lassen Peak lot), I continued on to the San Francisco State's "Sierra Nevada Field Campus" and observed near the Sierra Buttes for another 3 nights at Packer Saddle (7200') I'm still typing in my observing notes (about 200 objects observed) but here's what I looked at in terms of planetaries. All of these had been previously observed 4-10 times, but of course I still enjoy the views and comparing my notes afterwards with previous observations. As an example I've include 6 different observations of Abell 39! More notes to come ....


Abell 39 = PK 47+42.1
16 27 33.6 +27 54 34
V = 12.9; Size 170"

18" (7/14/07 - Lassen): easily picked up at 115x with an OIII filter. Appears as a weakly annular, sharply defined disc, nearly 3' in diameter. The rim appears unevenly lit with a couple of slightly brighter arc segments when I let the planetary drift through the field. Abell 39 was faintly visible unfiltered though there was a crisper view with a narrowband filter.

18" (7/20/06 - Lassen): 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. The thick rim is slightly brighter, though not uniform around, giving a weak annular appearance with an ill-defined, slightly darker center.

18" (7/18/04 - Sierra Buttes): viewed at 115x (20 Nagler) and an OIII filter. Appeared as a faint, fairly large, well-defined disc. With averted vision and concentration the rim is slightly brighter (possibly in arcs along the west and east sides), giving a weakly annular appearance. Very faintly visible unfiltered at 115x, though the shape is more formless without a crisp boundary, but it was now noticeable that the planetary is set in a rich star field.

18" (6/20/04 - Shingletown): swept up immediately at 115x using an OIII filter. Visible continuously as a crisp-edged disc, round, ~2.5' in diameter. Although there was no annularity there were subtle irregularities in the surface brightness. Barely visible unfiltered, though the glow seems to merge into the background sky without a distinct edge. Also, excellent view at 73x and OIII filter as the planetary was easily viewed continuously with direct vision.

17.5" (8/21/98 - Sierra Buttes): picked up at 100x with an OIII filter. Once identified, it was visible continuously with direct vision as a round, sharp-edged disc at least 2.5' in diameter. It appeared slightly brighter along the following edge. The planetary was even faintly visible unfiltered at 100x, though not as sharp- edged or well-defined and several faint stars were superimposed.

13.1" (6/18/85 - Fremont Peak): faint, fairly large, round. This planetary can just be held steadily with averted vision using an OIII filter which provides a superior view to the Daystar 300. ************************************************************

NGC 6337 = Cheerio Nebula
17 22 15.6 -38 29 01
V = 12.0; Size 49"x45"

18" (7/16/07): at 220x and UHC filter the "Cheerio Nebula" is a gorgeous annular planetary, ~45" diameter with a large, dark circular hole of 25"-30" diameter. The rim is uneven in surface brightness and perhaps brighter on the NE side. A mag 12.5 star is on the inside of the NE rim and a similar mag star is off the SW side along with a mag 13.5 companion. An extremely faint star is on the SSW edge of rim. At 323x, the striking rim appears brighter in a 50-60 degree arc centered on the brighter star on the NE side. The amount of structure was surprising given the low altitude at -38.5 declination. ************************************************************

NGC 6369 = Little Ghost Nebula
17 29 20.4 -23 45 35
V = 11.5; Size 30"

18" (7/14/07): striking view of this annular planetary at 280x. The 30" halo is punctured by a relatively large 18" hole. The rim is noticeably uneven in surface brightness with a brighter arc along the northern side. Spectacular at 700x and the brighter northern rim has a couple of very small brighter knots or stellar points.. ************************************************************

Abell 43 = PK 36+17.1
17 53 32.3 +10 37 24
V = 14.7; Size 80"x74"

18" (7/11/07): easily swept up at 115x and UHC filter as a crisply defined disc of 1' diameter located midway between a mag 9 star 4' NW and a mag 10.5 star 4' SE. Observing unfiltered at 225x, three faint mag 14-15 stars were superimposed over a very faint 70" disc. The mag 14.7 center is the brightest of the trio. The other two stars are mag ~15.3 and 15.5 at the south and east end and form nearly an isosceles right triangle with the central star. The planetary was visible unfiltered at 115x and surprisingly there was only a modest contrast gain using the filter. ************************************************************

IC 4673
18 03 18.4 -27 06 23
V = 13.0; Size 16"

18" (7/16/07): at 225x and UHC filter appears as a moderately bright mag 13 disc of just 15" diameter with a sharp, crisply defined halo. A mag 12 star lies 33' NE. At 323x the western side was perhaps slightly brighter. Located 45' N of Barnard 86/N6520. A very faint planetary, M2-26, lies 8' NNW. ************************************************************

NGC 6563
18 12 02.5 -33 52 06
V = 10.8; Size 50"x37"

18" (7/16/07): at 323x appears as a fairly bright, sharply defined disc, slightly elongated SW-NE and perhaps 48"x42". The disc exhibits a subtle irregularity in surface brightness but there was no evident annularity. A couple of extremely faint stars occasionally sparkled over the disc, though it was difficult to tell if one was situated right at the center. ************************************************************

Sh 2-68 = PK 30+6.1
18 24 58.5 +00 51 38
V = 11.2; Size 475"x330"

18" (7/11/07): swept up at 115x using an OIII filter as a very large, very low surface brightness hazy region, ~5' in diameter. Sharpens up in moments to a crisper edge. Just visible continuously with averted vision and the surface brighness appears fairly uniform, though may fade more at the south end. ************************************************************

Sh 2-71 = PK 36-1.1
19 01 59.3 +02 09 18
V = 12.3; Size 124"x75"

18" (7/14/07): viewed at 174x with an OIII filter as a roughly rectangular glow, elongated 3:2 N-S with a size of roughly 1.8'x1.2'. Appearly slightly brighter along the eastern edge with a small knot or brightening at the SE corner. The W and SW edges are slightly weaker and less defined with perhaps indentations or a scalloped edge. ************************************************************

NGC 6765
19 11 06.4 +30 32 45
V = 13.1; Size 38"

18" (7/16/07): this unusual planetary was picked up at 174x unfiltered as an elongated glow. The view is confused, though, as a star or knot in directly involved at the NE end along with 1 or 2 additional stars around the edges. Excellent contrast gain with an OIII filter as the edges sharpen up and the halo is elongated 2:1 SW- NE, ~0.6'x0.3'. At 225x, a mag 14-15 star is just off the NE end and the involved knot seems to occasionally resolve into a couple of faint stars just north of center near the NE edge. Finally, an extremely faint star occasionally sparkles at the SW end. ************************************************************

Abell 57 = PK 58+6.1
19 17 06 +25 37 30
V = 14.4; Size 40"x34"

18" (7/11/07): not noticed initially at 115x and OIII filter as I was searching for a larger object, but once picked up it was easily visible as a faint, fairly small, crisp-edged round disc, ~25" in diameter. Located 1.3' NW of a mag 11 star. Nice view at 160x with OIII filter and visible continuously with averted, slightly elongated, ~30"x25". ************************************************************

NGC 6781
19 18 28.2 +06 32 23
V = 11.6; Size 111"x109"

18" (7/14/07): at 225x appeared fairly bright, fairly large, round, perhaps 1.8' diameter. A brighter rim is evident, particularly along the entire south half and extending for nearly 180 degrees. The rim is weaker on the N side giving a partial thick "C" or crescent appearance. A mag 13.5 star is at the NE edge. ************************************************************

Abell 61 = PK 77+14.1
19 19 10.1 +46 14 36
V = 13.5; Size 201"

18" (7/14/07): at 73x and OIII filter appeared as a faint, round, low surface brightness glow, nearly 3' in diameter. Often the glow does not have a well defined edge but at moments the rim snaps into a sharper focus and the edge is fairly crisp and slightly brighter along the west side. Can hold continuously with averted vision. Removing the filter a faint star is at the N edge, 1.4' from center. A 4'x3' group of mag 11/12 stars lies ~5' SW and includes a 25" pair of mag 11 stars and a 30" pair of mag 11/12 stars. ************************************************************

NGC 6804
19 31 35.3 +09 13 31
V = 12.2; Size 62"x49"

18" (7/11/07): striking planetary at 450x, appeared elongated 4:3 WSW- ENE, ~60"x45". Three stars are involved including the 14th magnitude central star. A mag 12.5-13 star is at the NE edge of the halo and a mag 14.5 star is at the W edge with a mag 15 companion close SW. The surface brightness is irregular and weakest on the SW side and slightly brighter along the E side, giving a "horseshoe" appearance. ************************************************************

BD +30 3639 = PK 64+5.1 = Campbell's Star
19 34 45.2 +30 30 59
V = 10.5; Size 13"x10"

18" (7/17/07): picked up at 174x as a mag 10.5 star with a light red color. Excellent contrast gain by blinking with a H-beta filter! At 280x and 450x the central star is clearly surrounded by a small halo or ring, ~7" in diameter. ************************************************************

NGC 6826 = Blinking Planetary
19 44 48.0 +50 31 31
V = 8.9; Size 30"

18" (7/17/07): at 500x the "Blinking" Planetary is slightly elongated ~E-W, ~30"x25" with a bright 10th mag central star surrounded by a small, slightly darker annulus. The disc is pretty evenly lit but slightly weaker on the W or WSW side. In this aperture, there is no blinking effect as the central star is always visible. ************************************************************

NGC 6891
20 15 08.8 +12 42 15
V = 10.4; Size 12"x10"

18" (7/15/07): at 174x this small blue disc has a high surface brightness and is very prominent in the field. With direct vision the mag 12.5-13 central star is easily visible. At 280x appears as a very bright, small disc with an unusually high surface brightness and the central star shines steadily. At 700x, the extremely bright inner region is slightly elongated or lens-shaped N-S and is surrounded by a fainter outer halo or envelope that is still quite evident. ************************************************************

NGC 6894
20 16 23.9 +30 33 55
V = 12.5; Size 44"

18" (7/15/07): excellent annular planetary at 280x, ~40" diameter with a relatively large 25" darker central hole. The rim appears unevely lit and possibly brighter along the north side although there are a couple of extremely faint stars involved on the N or NW portion of the rim that may have affected this impression. At 700x the rim is clumpy and a bit weaker on the W side. ************************************************************

Abell 70 = PK 38-25.1
20 31 33.2 -07 05 17
V = 14.7; Size 45"x40"

18" (7/15/07): at 260x without filter, appeared faint, fairly small, round, 36" diameter with a hint of annularity. On the north side of a rim is a quite noticeable knot or brightening (this is an anonymous galaxy shining through the rim). With direct vision this knot is sometimes nearly stellar (core of the galaxy?) but with careful averted vision, the faint galaxy is definitely elongated ~2:1 WNW- ESE, ~18"x8". ************************************************************

Abell 72 = PK 59-18.1
20 50 02.0 +13 33 28
V = 12.7; Size 134"x121"

18" (7/15/07): located immediately at 73x using an OIII filter as a faint, fairly large, round glow with a bright mag 8 star just off the WSW edge. Better view at 115x, appearing ~100" diameter with a fairly crisp edge. Two mag 11/12 stars are just off the E and SE side and a faint star (central?) is in the interior. At 225x without filter, several faint stars are involved. ************************************************************

Abell 78 = PK 81-14.1
21 35 29.4 +31 41 45
V = 13.4; Size 113"x88"

18" (7/17/07): easily visible at 73x and OIII filter as a faint, moderately large disc, ~1.5' diameter. Cradled between two mag 12.5 stars off the NW and NE side and surrounding a mag 12.5 star central star. At 115x and OIII filter the planetary is sharply defined and has an even surface brightness. The central star appears offset from the center to the north side and the disc doesn't reach either of the nearby mag 12.5 stars. Located exactly midway between two mag 7.5/8 stars at 16' separation to the NW and SE. ************************************************************

Observing Reports Observing Sites GSSP 2010, July 10 - 14
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Adin, CA

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