by George Feliz
I arrived about 8:30 to clear skies and a warm breeze (which would continue until I left a bit after midnight). Marek, James, Peter and Phil T were already there with an XT10 (10" Dob), ED114 (114mm refractor w/ 600mm focal length), 6" Mak-Cass and a Tak refractor (4"?, f/8?). Phil was working on transforming photons into mega-bytes, but the rest of us were doing some not-too-serious visual observing. I used my homebuilt 6", f/6 Dob.
The seeing started out reasonably promising, but degraded through the evening. I base that on splitting the double-double which was easy at 100x early, but very marginal near midnight. Nu Scorpii was not a clean, steady split at any time, although the best attempts were early in the evening.
The skies were darker than normal for MB, possibly due to some fog or haze down in the lowlands. The Milky Way put in a nice appearance, although not as bright as Coyote Lake (by way of comparison). The light domes to the north, east and south were diminished, although limiting magnitude was not as good as Danville.
I observed about 3 dozen objects over the evening, including several targets from Karkoschka. I enjoy this small atlas a lot, and all of the targets are accessible with a 6", although some require darker skies. I took advantage of the fine MB southern horizon to look at many OC and GC in the Scorpius/Sagittarius region.
The lowest object I observed was the globular NGC 6388 with a Dec of -44.7.
The farthest object I observed was the mag 11 galaxy NGC 5746 on the Libra/Virgo border. At 90 Million Light Years, this edge-on galaxy did not show much detail. It is also quite close to the mag 3.7 star 109 Virginis which interferred with the show. It was best if 109 was placed just outside the field.
The best comparison objects were the Draco galaxies NGC 5907 and NGC 5866 (known to some as M102). 5866 is a bright mag 10 elliptical, and nearby 5907 is similar magnitude, but a much lower surface brightness and edge-on. The needle shape was held only with averted vision at 100x in my small scope. Moving over to Markek's 10" dob, I confirmed the galaxy and was able to view it directly with the nearly 3x increase in light gathering. Yes, aperture does win. Repeating the view with James' ED114, the smaller scope actually showed a very pleasing image which I attribute to its higher contrast.
Best mooched views were the wide-field views throught James' refractor with a 31 Terminagler. I propose that it be mandatory that someone brings a nice wide-field scope for all MB sessions. :-)
In all, a very enjoyable session with good company. MB had much better weather than down in the valley - a reverse-Marek-effect.
On the way home I came to a complete stop on Page Mill to allow a confused doe to find her way to safety. She had that "astronomer-in-the-headlights" look...
Clear Skies,
Posted on sf-bay-tac Jul 07, 2004 10:17:26 PT
Converted by report.pm 1.2 Jan 03, 2005 19:12:09 PT