In Pursuit of Ursa Major

1997 Dec 29

I got lost several times trying to find my friend's private observatory, in the Sierra Nevada foothill community of Bear Valley, California. It was dark -- very dark, for those used to suburban sky, which is why several of us had responded eagerly to the generous invitation to come out and observe during the week after Christmas. So although the roads, turnouts, and gates were decently marked, I could not see them, nor could I see the boxy structure of the roll-off roof building 100 meters beyond the fence at the shoulder. I was reluctant to try at random -- for all I knew, the neighbors had shotguns and packs of attack dogs -- but finally I picked a likely driveway, turned in, and nearly ran over a big Dobsonian. "This must be it", I thought, as I fumbled my way further in, lights on "dim", but nobody was home. They'd gone for dinner. No matter, my friend had said that if I arrived when no one was there, just go ahead and set up. So I found a dark corner of a field, hauled out my Intes 6-inch f/10 Maksutov, and started observing.

The drive to the site had been easy -- it is only three hours from the part of the San Francisco Bay area where I live. There are several ways to get to Merced, California, some by freeway, and some by side road through pretty parts of California's Great Valley. It's less than an hour more to the site, through rising, rougher, and more heavily forested countryside in the western Sierra foothills.

Did I say it was cold? Well, it actually wasn't, not by the standards of where I grew up, but temperatures were below freezing, and I did have occasion to put on my powder pants, down-filled booties, and three layers of sweat-shirt, down vest, and jacket. But the wonderful dark Sierra sky was worth a little discomfort, and soon I was happily chasing galaxies at 97x, listening to the rustle and scurry of happy little woodland critters in the deep night around me.

After an hour or two, the diners returned. I walked down the road toward where they had parked. "Hello," said someone cautiously, to which I replied in my deepest and most mysterious voice, "I am the ghost of James Lick ...". Fortunately, I was in the right place after all, for that remark was met with laughter rather than alarm.

Four of us were present -- my friend, her husband, me, and one more observer. First order of business was a tour. Having been shown where the sanitary facilities were, I was eager to learn more about the observatory. It is ten feet by twelve feet. The roof rolls off to the north, leaving a wall four or five feet high surrounding the pier for a Celestron 11, which tonight had a four-inch Vixen fluorite refractor piggy-backed. There is a level area for setting up the 18-inch Obsession, and much flat, open land for portable telescopes. The owner had done a fine job on the construction. I was envious.

We chatted for a while about astronomical topics, then I changed the subject to one of my other interests. "What kind of wildlife do you find around here?" "Well," she responded, "I found two bear tracks this morning." "Oh ... er ... wow!" I replied thoughtfully, remembering those woodland rustles I had been listening to, all alone, for an hour or so. I guess I thought they called it "Bear Valley" because it had squirrels. Then, making a mental note to be sure not to put the cookies between me and the car, I went back to observing.

The bear's, er, lion's share of my observing for the next three evenings was the faint half of the 2514 or so faint objects discovered by William Herschel, the same program with which I have bored Internet readers for six months. I have logged over a thousand of those elusive fuzzies since June, and my results continue to confirm that a six-inch telescope, carefully used in dark sky, can pull in nearly all of the "big" Herschel list. It may be useful to reiterate that I have been using rather more magnification than many would think appropriate for such work with six inches of aperture: I experimented with 47x, 75x, 94x, 97x, 121x, and 150x, and finally settled on 97x -- a Meade 15.5 mm Research-Grade Erfle -- as "right" for the Intes. I remember being dazzled at first, when I realized I could work to almost 15th magnitude with a six-inch (remembering that galaxy magnitudes are notoriously inaccurate), but I can, and I encourage others to try.

I did not stay at my friend's property. Rather, I rented a room in nearby Mariposa, whose business is mostly tourism associated with nearby Yosemite National Park. Winter is the off season, so the E. C. Yosemite Motel was willing to rent me a huge single room with a huge king-sized bed, for the low price of $30 US per night. The heater worked, the TV had HBO, and all was satisfactory. The only surprise was that the tile floor of the bathroom was insufficiently insulated from the cold ground beneath, resulting in an abrupt transition to complete wakefulness for early-morning staggerers who trod thereon.

Mariposa is a nice little town -- if I had been more awake during daylight hours, I might have seen more of it. I can confirm, however, that the local Pizza Factory and the family-run Happy Burger serve good food at reasonable prices. I chose these restaurants because they were the only ones in town with cars parked in front of them.

We were lucky to have three clear nights in a row in December. The second night was warmer, with enough moisture to cause dew and frost. The third had a temperature between the first two, but it was dry. One more observer joined us on the second evening.

Though the six-inch pulls in most of the Herschel stuff, there are a few objects beyond it entirely, and a few more cases where it can detect closely adjacent galaxies but not resolve them as separate. In such circumstances, more aperture is useful. "I'm a bear", I declared, walking up to the observatory to ask to use the C-11 to chase down some elusive fuzzies in Ursa Major -- bears again! -- near the wide, bright double star that Messier cataloged as no. 40 in his list. This area offers an interesting contrast in difficulty of observation. M40 is a binocular object, and within a quarter degree west lie two galaxies, NGC 4284 and 4290, which are bright enough to be easy in a six-inch in half-way reasonable conditions. The somewhat fainter NGC 4335 lies not quite a half degree north of M40, and to its east-southeast, a quarter degree away, are two similarly bright galaxies, NGC 4364 and 4362. I could see all of these in the Intes, but I could not see the faint companion, NGC 4358, of the westernmost of that latter pair, NGC 4364. Neither could I see any trace of a close pair of galaxies about a degree east-northeast, NGC 4547 and 4549.

At 108x, the C-11 found 4547/4549, and resolved them as separate, but the companion to 4364 continued elusive. One of the other observers had an 18-inch Dobson set up, so we tried it, and at 91x, NGC 4358 was visible. I would rate 4547/4549 and 4358 the most difficult objects that I have encountered on the Herschel list so far.

After three nights observing, I was tired, so I headed home the next day. I seem to have lucked out on the weather, for that day and the next one brought high clouds and haze to the Bay Area. I am very greatful to my friend for providing a holiday occasion to get away for some dark-sky observing; perhaps she will invite us back again in the future. Maybe I will even get to see a bear.

Jay Reynolds Freeman; 1997 Dec 30