by Marek Cichanski
I arrived around 7pm, and I was somewhat surprised to find that Matt Marcus was the only person there. Some clouds had started to build up, and Matt was thinking of heading home, but they started to dissipate again before too long. I set up my ED80 with a full arsenal of Kendrick heaters and Matt and I started Messier-hopping.
We saw most of the usual suspects that you'd expect to see at this time of year, no surprises here...
We tried like crazy to see NGC 891, which I've seen from MB in that scope, but we couldn't quite do it. Sky must have been just a skosh too bright, or transparency a bit lacking due to the humidity. It was fun to try, though.
The seeing was considerably better than either of us had expected. As Andrew pointed out earlier in the day, the seeing is often poor in the wake of these cold front passages. But in fact, we had very little naked-eye twinkling, even on Sirius. It was quite steady. And we had some very nice views of multiple stars, such as Polaris, Castor, Sigma Orionis, Eta Cas, and Iota Cas. Four stars in the Sigma Ori system were nicely visible, as were the four stars of the Trapezium. We went after the E and F stars, and I think that we more or less got them. I could see the E star (if I have my E&F stars correct) with averted vision, and the F star appeared in the first diffraction ring of the brightest Trapezium star. Again, quite nice seeing for a cold-front-passage night. And speaking of seeing, we had some very nice views of Saturn, with the Cassini Division visible and a nice little band on the planet, plus Titan and maybe one or two other moons.
Another fun thing that we did was to pull out the spectroscope. Even with only 3" of aperture, we saw some neat spectra. The spectrum of Betelgeuse showed many molecular absorption bands, and the spectrum of Sirius had the most amazingly razor-sharp H-beta and H-gamma lines. (We even caught glimpses of the H-alpha line, but it's so far in the red it's awfully hard to see. It's a vivid demonstration of how the visual acuity falls off at those wavelengths.) Saw some nice detail in the spectrum of Capella, it was right at the edge of visibility, much like looking at planetary detail. Saw similar edge-of-visible detail in the solar spectrum reflected off of Mars.
Clouds came and went, but I'd say that it was mostly clear. There was, of course, major dew. If you didn't have nichrome wires and some 12v DC, you weren't going to get any observing done. But with the heaters it was doable. It was 44 deg F when I left a little before midnight.
As with all such trips, it's always really gratifying to get in an observing session between storms. Really helps to take the edge off of that rainy weather.
Posted on sf-bay-tac Dec 29, 2005 00:49:48 PT
Converted by report.pm 1.2 Mar 16, 2006 22:58:37 PT