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Observation Report
Lake Sonoma, Wed., Jan. 16, 2002

by: Robert Leyland

It was crisp and cold Wednesday, but what a glorious day, clear air visibility seemed like 100 miles :-) Well worth taking a trip up, as Sat the moon doesn't set until nearly 11pm.

Driving up to LS was a bit of a chore, for others contemplating mid-week sessions beware traffic through northern Marin and Santa Rosa. Just north of Novato it slowed down, for no apparent reason before opening up. In Santa Rosa they are doing freeway widening, and the traffic gets spooked by the concrete dividers, and slows down again. It took almost two hours, to make, what is usually a one hour drive. So I'd recommend leaving early, or driving up later after it clears.

Of course, while I'm listening to the traffic reports, I hear that Geyserville is predicted to be the cold spot for the entire Bay Area overnight, approaching 25F (-4C), youch, that's the next town north from Lake Sonoma!

In my reporting I am trying to include a little better directional, and distance detail. My reports tend to be impressions-from-the-eyepiece, and I'd like to retain that flavour balancing more substantive information, so as not to be too dry. Feedback is appreciated.

Technical data
Date/Time: 16 Jan 2002 - 1930-1100 PDT (UT -8, or 0330-0700 18 Jan 2002 UT)
Location: Lake Sonoma CA, 3843'N 12302'W Elev ~900 (Grey Pine Flat)
Weather: 4-6C Temp, 75%-82% Humidity
Instrument: 17.5" F5 Dob, Telrad + 9x50 finder scope
Oculars: Pentax XL eyepieces
Seeing: LM 6.5+, transparency 9+/10, steadiness 9/10, zero wind

The day before we had reports of turbulence upsetting many observers views, but today was very calm. The various weather web sites had predicted clear skies, with a mild breeze, and some had suggested that it might get a little less transparent late in the evening.

It sure was cold, even at 6pm when I arrived, but very dry. I drew sparks from the truss poles on my Dob! About 6:30 Steve Gottlieb came in, and we setup and chatted, about mirrors, computers etc.

Early evening I attempted to get a few more DSOs in Cetus, but I've come to realize that diving in, after difficult things, right away is not a good idea. Like any physical activity, you need to warm up, condition those muscles etc. Since I hadn't, it took me a while to get going; finder not aligned properly, trying to star hop with a high power eyepiece... silly little errors, best caught on easy objects, when you know what to expect.

Once I got going, well, it sure was a pretty night:

NGC 681 Galaxy in Cetus is an easy start, a small face-on ellipse. Right next to a field star, so that it is easy to find, but close enough to 55 Cetus, that the bright star is bothersome. Repeating my observation from last month, it is bright, circular with a distinct core.

Nearby is NGC 701, another galaxy, smaller and distinctly dash shaped, almost edge-on oval. Not much in the way of detail, however a nice triangle of three field stars (maybe 12th mag) lies approximately 10' to the SE.

On the other side of 55 CET (to the S) lies NGC 720. This galaxy is just off the tip of a pentagon of stars (pointing away from 55 CET). A nice, elongated oval, galaxy oriented NE/SW with a slight increase in brightness at the NE end.

Through the evening, Steve G called me over to look at a number of objects he was hunting, including at least three planetary nebulae, which were quite interesting and regarded them as challenging. However, this time he had put in an H-Beta filter and was viewing the California Nebula. Conditions were just right, dark night, clear skies, and the nebula very near the zenith. Near enough to "Dobson's Hole" to give us some difficulty maneuvering.

We spent several minutes scanning the nebula, tracing the convex curves of the "coast" to the large flaring area at the west end, and the deep hand-shaped dark incursion at the east end, that splits the nebula in two. Often comparing our views with the photograph in NSOG.

For the curious the California Nebula NGC 1499, is in Perseus, is next to Epsilon Perseus (46 PER), along the "leg" of Perseus that reaches towards the Pleaides.

It's really big, I mean really, really big, 3 x 1 big, appearing visually larger than the Andromeda galaxy, but it's barely visible unfiltered... a UHC filter brings the contrast up a bit, but _nowhere_ near the H-Beta. (Note to self, got to get one of those!)

I returned to my galaxy hunting in Cetus, and found the triplet of NGC 1035, 1042 and 1052. 1035 is a delicious edge on oval with a nice little field star right at the tip. While 1052 is a bright oval, that should be quite visible in an 8". Completing the triangle is 1042 a faint spiral. Initially this appeared as a large diffuse area, but a little averted vision brought out some spiral shaped arcs. By judiciously placing the galaxies near the edges, I could bring all three into view at once: a spiral, an edge on, and an oval (110x approx 0.6 TFOV).

Once again Steve distracted me, in a most welcome way. This time in Orion, right on the border of Gemini is NGC 2174/75, which he was viewing to follow up on an early observation. I expect he will report his findings also.

This is a pretty neat combination of am open cluster (2175), on top of an emission nebula (2174), with a bit of a twist. We spent a goodly amount of time scanning this region, with and without filters, and at a variety of magnifications.

Steve noticed that an area of the nebulosity appeared much brighter, yet when an OIII filter was used it darkened, and the rest of the nebula really stood out. He has some interesting notes that he had researched about the object, and indeed the description in NSOG hints at the mystery.

Without a filter this small part of the nebula (approx 10' NE of the bright central star) is really the only visible piece. Drop in an OIII filter and it all but disappears, indicating that it is most probably a reflection nebula, while the emission nebula surrounding the star extends out as far as this faint patch, and can easily be seen contrasting against the darkened sky. The main nebula is slightly brighter on the N side, and to my eyes appears puffy.

NGC 2175, the cluster, has two parallel lines of stars running E-W one to the N of the central star and one to the S. Both lines have double stars within them.

The whole region is really neat, and provides one more reason to visit the constellation Orion.

Another of Steve's recommendations is IC 443, a supernova remnant in Gemini. It is easy to find, being midway between Mu and Nu GEM, at the feet of the constellation, approximately 3 SW from M35. It is a nice comma shaped streak, directly visible and much enhanced with an OIII filter. We looked for more extensive bits of the nebula, and saw some dim nebulosity flaring off the NW end. The outer edge is distinctly sharper than the inner edge.

We noticed a band of hazy cloud rolling of the zenith, right on schedule from and Atilla Danko's Clear Sky Clock, at almost 11pm.

To close out the evening, I took a peek at M42, and the trapezium. Seeing really was good as the E & F stars were quite easy to see at 110x, and a small pair of stars, that I had never noticed before, were visible off the E-star side.

I packed up and left, noting that the temperature had dropped to 4C (38F), the point at which water has its highest normal density, but still well above the predicted low. If I wasn't working the next day, I'd have stayed a few more hours!

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