by Paul LeFevre
A few TAC-South members gave the Observatory Campground on Palomar Mountain a good tryout this weekend...here's a report of what we found.
Friday afternoon I packed up the family and telescope, and headed up the mountain. We arrived at the campground at about 4:00 PM, and found completely overcast, gray skies. Ever the optimist, I began setting up the tent and camp anyway. Bob Nanz arrived at about 5:00 PM, and said the satellite loop for the evening looked "iffy," but that it would be better for Saturday. Just before Dark, Don Clement arrived as well, and despite the ugly sky we all got our scopes set up, with Don setting up a very nice home-built binocular mount for some big binos.
As darkness fell, the sky improved dramatically. By the time we were well into twilight, there were only some hazy clouds in the South, with the rest of the sky very clear and transparent. I set about doing a drift polar alignment (my goal for the weekend being mainly astrophotography), and by the time I finished the Milky Way was showing all of its glory. I would estimate the skies Friday night at about 9 out of 10 for seeing conditions (VERY steady!), and about 6 out of 10 for transparency, with periods of slightly better transparency. Limiting naked-eye magnitude was about 6.5 - 7.0. Very good indeed! There was a very slight light dome to the North-East (from Temecula) and to the South-West (from Escondido), but neither was very intrusive.
The horizons at the Observatory campground are...well...crappy. The campground is ringed by hills and tall trees on all sides. At the middle of the open area, you lose about 8 degrees of Southern horizon, 12 degrees in the East, 15 in the West, and 10 or so to the North. The good news is that the "artificial horizons" cut off most of the light pollution, leaving the sky that is visible very dark.
Temperatures were very pleasant, getting down to only about 65 degrees at midnight, with alternating cool and warm breezes blowing through occasionally (very mild breezes, less than 5 MPH I would guess). We spent an enjoyable night finding targets in binoculars, naked-eye, and in Bob's 16" dob and 12" LX200, while my 10" LX200 was taking long exposures all over the sky. Don packed up shortly after midnight for the drive home, while Bob and I were camped for the weekend.
The temperatures during the day on Saturday were almost brutally hot -- it got up to 99 degrees according to my car's thermometer! My family and I spent periods inside the car with the AC on to cool off...but the skies looked very clear and promised a good night for Saturday. We took a little side trip up to the Observatory proper to have a look at the Hale 200" scope at around 2:00 PM, and when we started home we noticed a huge plume of smoke to the East -- the brush fire in Temecula that as of this morning had consumed 2500 acres and is still not contained. Shortly after arriving back in camp, the smoke moved over our campsite, and ash began to rain down like light snow. We figured we would have to head back down to town, both because of the smoke and ash, and because we would have nothing to look at that night! Bob and I took advantage of the dense smoke, however, as a solar filter -- and snapped a few digital camera pictures of the very red sun and sunspots through my ST80 with no solar filter! All of the cars and scope covers had a layer of fine ash on them, and we were getting tired of breathing the stuff...
Once again, though, the mountain cooperated with us. The temperatures had dropped dramatically as the smoke covered the sun, and just after sunset cool breezes started to push through the area, and the smoke began to dissipate. Just like the previous night, by twilight we were once again looking at clear skies, with almost no trace of residual smoke in the air. You just know that it must have been these characteristics that caused the site to be selected for the 200" scope back in the 30's! Transparency was actually a little better than Friday night, and seeing was just as good. We got great views of the Veil Nebula through Bob's 16" dob with no filter, and every target we looked at was steady and contrasty. My scope once again spent most of the night taking photos...I took a short break to do a visual tour for a father and son from Texas who came up with their TV-85. They were visting the San Diego area on vacation, and found TAC-South on the web. Reading that folks would be up at the campground on Saturday, they made the trip up, and were very pleased with the dark, steady skies. Bob and I helped them find some showpiece objects in their own scope, while showing off the power of aperture in our own scopes. I stayed up Saturday night until around 3:30 AM Sunday, to catch views of M45, Jupiter, and Saturn as they rose up in the East. It was another great night, and after a few hours sleep we all packed up and made the 30-minute drive home.
Those of you who gave up on the mountain because of clouds and/or smoke missed some good nights! I'm beginning to think there's something special about the air currents over the mountain, because it continually surprises me with good seeing when all around it looks to be not worth the trip.
As far as the campground...the facilities are good, and it's nice to have built-in telescope pads (with tiles with "N" on them pointing towards North!). Saturday night we had to put up with some drunk Marines in one campground, and quite a few people driving through until after 1:00 AM with their brights on or bright lanterns in their campsites (even the ones with the dark skies notices on them!). Bob and I made a few rounds to these folks, and they were all very polite in turning off their lights, and a few of them trundled over to have a look through our scopes. The ranger in residence (Ken, a very nice guy) said the weekends in July/August were the worst for "riff-raff," and that most times there were no such problems. As Don mentioned, the parasite-carrying racoons and mountain lions were mentioned to us by the ranger, but the only run-in I had was at about 3:00 AM Saturday/Sunday when a racoon tried to make off with my trash bag; I didn't SEE any mountain lions, but we did hear one growling and yelping about 20 minutes later (possibly enjoying a racoon meal?).
Palomar mountain will continue to rate high on my observing list rankings, but the Observatory Campground itself is not the best place for a Summer outing. Temps in the daytime are very hot, there are too many unruly/non-astronomy neighbors, and the horizons are only fair. I'm pretty sure that during the Spring/Fall, when the site is less crowded, that I'll still spend time up there despite the horizons -- it's just so convenient to park and tent next to your scope! Otherwise, I'll continue to use my "turnout" spot, and look for other good places on the mountain. The seeing conditions are just too good to give up on. There were some good spots on the road to the observatory, and the observatory parking lot would be GREAT...gotta see if I can convince CalTech that I'd be a good night-time neighbor...:)
Paul
p.s. I'll put up some of the photos I took as soon as the roll is developed.