September 16, 2009: Lake Sonoma

Carter Scholz

I arranged to meet Steve Gottlieb and Dana Patchick for a short night at Lake Sonoma before leaving on a longer trip. Traffic was mercifully light all the way up.

Dana arrived prepared with charts to look for Jupiter's sixth discovered moon, Himalia. With a separation tonight of 45 arc-minutes and a magnitude of 14.8, he though it achievable in his 13", and it was. The view was better in Steve's 18", but it showed up in Dana's 13" and my 12.5", identifiable because there were no stars of near that magnitude near its position.

Steve also had a couple of exotic targets: near Herschel's Garnet Star, planetary nebula PM1-333, which has been photographed but not observed visually by more than a few people. Surprising, because it is quite bright, showing real detail in 18", and not difficult to see in 12.5". I have seen NGC PNs less impressive.

And reflection nebula vdB 1, less than a degree from Caph, beta Cas. A substantial, somewhat off-center brightening around a trio of stars, with a dimmer, ancillary brightening around one of a nearby, fainter trio. This too was visible without difficulty in 12.5". (Steve reports that the ancillary brightening is cataloged as Herbig-Haro 164.)

My own plan was more pedestrian. I continued through Luginbuhl & Skiff's Obsrerving Handbook, first scooping up a few objects in the west before they vanished for the year. To increase my interest in them, I'm trying to give open clusters a Trumpler classification.

5701: G Vir, smallish, elliptical NS, even
5876: G Boo, dim, diffuse, then brighter core, irreg appearance
6373: OC Sco, >12 stars resolved, brightest in center; I3p
6563: PN Sgr, bright, round, easily vis w/o filter; about 1' oval, annularity not seen
IC1297: PN CrA; slightly non-stellar; much brighter w/O3; no detail
IC1310: OC Cyg; 12 stars over bg glow; II3p
6883: OC Cyg; 7 stars in rough anchor shape; I1p
6894: PN Cyg; big ghostly glow, slightly oval, hint of annularity. O3 not helpful, UHC slightly improved contrast
IC4996: OC Cyg; 15 stars in elongated pattern over bg glow, about 2' x 6'; II3p
IC1318: neb Cyg; considerable glow around gam Cyg, better at low power
The most interesting L&S object was Campbell's Hydrogen Star, PK 64+5.1, near Albireo, barely distinguishable from any other 9th magnitude star. This is a Wolf-Rayet shell, emitting primarily at hydrogen-alpha and -beta wavelengths. At low power it appeared slightly pinkish. At 320x it was slightly nonstellar. There was no visible response to O3 filter or UHC. In H-beta, its two neighboring stars were substantially dimmed, the target becoming the brightest of the three, and it appeared to show a small disc. But I am not certain that the disc was not an effect of seeing and brightness. More aperture and magnification would be helpful on this target.

A very enjoyable night with some very special targets, thanks to Steve and Dana.