Willow Springs in the shadow of a 33" (9/15/07)

by Steve Gottlieb

I joined Mark Wagner, Richard Navarette and Bob Jardine last Saturday night at Willow Springs, roughly an hour south of Hollister in the Diablo Range. With our three 18-inch scopes (two Obsessions and a Starmaster) and a 12.5-inch Portaball, our scopes were complete overshadowed by a homemade 33.4-inch f/5 monster owned by Kevin Ritschel .

Transparency was good enough to clearly show the Gegenshein, although not up to the best nights at this site. I spent the night working on a variety of faint planetaries and HII regions, interrupted several times with climbs up a huge ladder to peer into the eyepiece of the 33". We were treated to views of IC 1295, NGC 7479, NGC 7662, NGC 246, NGC 247, NGC 253, NGC 891, Abell 426, NGC 1300, NGC 1516 and more.

Here are a few objects I took brief notes on in the 33":

NGC 246
33" (9/16/07): gorgeous annular planetary viewed at 200x. The thin brighter rim was striking and varied in brightness and thickness around the periphery. The rim is brightest along the western or WNW edge and weakest on the east side. The interior was darker but irregular in surface brightness.

NGC 1300
33" (9/16/07): at 200x a bright bar is oriented ~E-W. At the west end of this bar a faint arm hooks sharply to the north and begins to hook back to the east.

IC 1295
33" (9/16/07): at 200x appeared weakly annular with a slightly darker hole in the center and slightly brighter rim except on the west edge where there was an indentation or darker notch taking a small bite out of the rim.

As far as observations in my mini-18", I took a look at a few large HII regions and several faint planetaries. One unusual object was an interesting "S" shaped filament dubbed the Propeller Nebula (Simeis 57 = DWB 111/118/119). You won't find it plotted on any standard sky atlas although it's a fairly well known target for imagers (see http://tinyurl.com/ytzjz9) and I happened to notice it recently on a wide-field image of the Gamma Cygni region. There likely have been very few visual sightings of this nebula as only one observation showed up on a google search. This obscure object is located roughly two degrees north of the IC 1318 complex (Gamma Cygni Nebula) and at least part of it was visible using an H-beta filter in my 18-inch.

Simeis 57 = Propeller Nebula
20 16 17 +43 43.0
Size 20'
The Propeller Nebula was viewed at 73x using an H-beta filter. Although very faint, two sections of this elongated "S" –shaped emission strip were visible. The most prominent section was at the north end and consisted of a 5'x2' strip elongated N-S. Just north of this strip are mag 8.8 and 10.5 stars and the nebulosity extending south from these stars for roughly 5' in the direction of a bright isosceles right triangle of mag 7.5-8 stars (sides 4.5', 4.5' and 6') including the double star Fox 252 (8.9/10.4 at 19"). Two nearby mag 10 stars complete a pentagon. The middle section of the Propeller (to the west of the pentagon) was extremely weak or likely missing but at the south end a smaller 3'x2' piece, elongated N-S, was faintly visible to the SSE of ?2659 (8.4/9.5 pair at 20").

Another object I was hoping to observe was SB 20, a small planetary discovered in 1999 in an H-alpha survey. A first visual sighting was reported by Kent Wallace just a few days earlier with his 20-inch.

SB 20
18 49 24.3 -19 52 16
Picked up at 300x as a very small, faint glow ~5" diameter attached on the NW side of a mag 14.5 star with a fainter mag 15.5 star sometimes visible on the NW edge of the glow. Adding a DGM Optics NPB filter, the contrast increased significantly and the planetary was visible continuously with averted vision as a ~10" disc. Surrounded by a small, partial 2' ring of mag 13-15 stars.

Most of the other planetaries I looked at afterwards were faint Abells – always a fun challenge to track down in dark skies…

Abell 49
18 53 28.5 -06 28 33
V = 16.2; Size 35"x33"
Not noticed at 174x unfiltered but adding an OIII filter visible as an extremely faint, small glow, ~25"x20" by letting the field drift. Located 2' SE of a mag 9.5 star and 2' NE of a mag 11 star. VIsible roughly 1/3 of the time with averted although occasionally visible several seconds at a time as a crisply defined disc.

Abell 53
19 06 45.8 +06 23 56
V = 16.3; Size 30"x27"
At 175x and DGM Optics NPB filter, visible as an extremely faint, fairly small, round disc, 25"-30" diameter. Required averted vision and only visible ~50% of the time, though occasionally could hold for several seconds at a time. A mag 13.5 star is located 1.6' N. This star is collinear with a 40" pair of mag 11 stars located 5' NNW of Abell 53.

Abell 62
19 33 18.3 +10 37 01
V = 14.7; Size 161"x151"
At 115x and OIII filter appeared very faint though not difficult, large, round, low even surface brightness, ~2' diameter. Situated in a rich star field with a mag 10 star just off the NW edge. A mag 11 star is just off the NE edge (this star is at the end of a chain of stars to the SE without a filter). A couple of faiinter stars are at the south edge.

Abell 67
19 58 27.0 +03 02 52
V = 13.6; Size 69"x61"
At 115x and OIII filter appeared extremely faint, moderately large, round, ~50" diameter. Requires averted vision and visible between 1/3 and 1/2 of the time with concentration. Located 1.8' SSE of a mag 13 star. Two mag 14/14.5 stars are 1.5' NE.

Abell 71 = PK 85+4.1 = PN G084.9+04.4 = Sh 2-116
20 32 23.2 +47 21 04
V = 14.5; Size 165"x150"
At 175x and DGM Optics NPB filter appeared extremely faint, fairly large, roundish, ~2' diameter. Three stars are superimposed, one in the interior and two near the south edge. Generally this difficult planetary was only glimpsed as a very low surface brightness hazy glow without a well-defined edge, but occasionally it was more confidently visible as a disc.

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

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