Dinosaur Point Observing 16 and 17 March, 2001

by Jay Freeman


I took Harvey, my Celestron 14, to the Dinosaur Point boat launch area parking lot at San Luis Reservoir, on both Friday 16 March and Saturday 17 March, 2001. The nights were similar in quality -- good transparency most of the time, with cloud and haze always threatening and occasionally present -- but different in comfort and company.

On Friday, it was chilly, and I was the only observer there. I wasn't entirely alone, however, for a car or two of night fishermen pulled into the other end of the lot for a while, and there were coyotes, and assorted half-heard rustles and uncertain grumbles in the underbrush a scant few meters from my van. On Saturday, conditions were warmer, and the zoo was noisier and more visible: Someone reported a count of 47 telescopes present at sundown, and a few more astronomers showed up later on. Equipment included many Dobson-mounted Newtonians, with apertures up to 25 inches, and lots of Schmidt-Cassegrains. Someone had a 13.1-inch Newtonian on a German equatorial mounting, with a gorgeous tube -- wood veneer over fiberglass, finished so smoothly you could all but see your face in it. There weren't any of the usual bunch of large refractors, though, which was a little surprising, as Mars crept over the top of the hill, as bright as Antares, while many of us were still awake and observing. But I am getting ahead of myself.

The mission for me for both nights was more deep-sky survey from the pages of Millennium Star Atlas. I had finished observing through 10 hours of right ascension, and was eager to press on eastward. I worked late on Friday, rather than fight commute traffic, and did not arrive at the site till about 9 PM. By the time I was set up, 10 hours was far enough up toward the meridian that I could start work immediately at the southerly limit of my survey -- the charts that run from 33 to 39 degrees south declination -- and since the sky was dark and the transparency was good, that is precisely what I did.

The weather had been deceitful and threatening. A long thick band of glop lay across the North Pacific, from the state of Washington out to the north of Hawaii, and patches of high cloud spilling off its south edge kept sweeping across the Bay area. The high cover was evidently enough to deter many observers, but by the time commute traffic had thinned, so had the clouds, so my own expedition set forth. During about three hours of setup, clouds blocked my view for perhaps half an hour, but transparency was very good between them, and the sky was very dark -- I was occasionally spotting galaxies in Abell clusters just above the ridge lines to the south of the parking lot -- so I was quite happy. The relative humidity started in the mid 50 percents, rose to past 85 percent, and was declining through 80 when I started taking down my setup. There was light dew on the black vinyl seat of my observing chair, but a Kendrick anti-dew system at 30 percent of full power was more than enough to keep Harvey's corrector dry, even with no dewcap.

I logged a few more than 70 objects before leaving, and worked the 36-south band around to almost 13 hours right ascension. The sky was clearing as the Moon rose; had I been interested in brighter things, I could have continued observing much longer.

On Saturday, I left home in late afternoon, and arrived just before sunset, bearing two large pizzas. One advantage of lots of people is that I don't waste much time getting rid of pizza. I was able to start set-up almost immediately, and began observing in late twilight. Weather was calmer, warmer, and clearer than on Friday, though there were occasional clouds on the horizon and perhaps some haze overhead now and then. Humidity was similar to the night preceding, and my measures to combat it were the same. Yet I should have put on the dewcap -- the cool temperatures reduced my battery's output, and its voltage had dropped too low to power Harvey's Losmandy G-11 by half past midnight. With the dewcap on, I could have used a much lower setting on the Kendrick, and saved power.

My program was more Millennium stuff, but since the meridian at sunset was at only six hours right ascension, I started the 10 to 12 hour strip well north of the celestial equator, and worked southward as the Earth revolved. This area begins to skirt the western boundary of the Virgo galaxy cluster; there are lots of objects, but they are close together. With a decent finder and moderate skill at star-hopping, locating things rapidly in such a part of the sky is a cinch. Particularly fun was a modest cluster of galaxies in Centaurus, near 13:40, 33 south. In this area the galaxies plotted on Millennium aren't as bright as in the heart of the Virgo cluster, but they are almost as dense. The area is much smaller than Virgo, of course.

I did not need to stop observing when my battery became too weak to power the G-11 -- after relubricating, its bearings are sufficiently smooth that I can use the telescope effectively at low magnification by hand-slewing. Yet I was tired, and I had observed 259 objects already that night, so I packed up and wandered around, chatting, for a while. I had a very nice view of NGC 4565 -- my favorite telescopic galaxy -- in an 18-inch Obsession at 100x. The dark lane of this edge-on spiral was well delineated by bright matter on both sides, and a star-like nucleus peeped over it, out of the central bulge. Mars popped over the ridge line at about that time, but I couldn't find anyone looking at it, so I left.

It was a fine night.