The June 7, 1997 Star Party at Fremont Peak State Park, California, was alternately fogged out and blown away. When I arrived at about 6:30 PM, the sky was clear, but a strong sea breeze was bringing fog on shore and filling the coastal valleys -- the top of the fog in the valley south of the peak was over a thousand feet higher than over the more open area to the north.
I set as high as I could. Before long, gray tendrils began to stray over the state park. The fog in the valley to the south sloshed like soup in a bowl or water in a bathtub, with a period of about five minutes. When it sloshed toward us, a wave of fog overran most of the setup areas and spilled down the north face of the peak. A few minutes later, on the opposite phase of the wave, the fog tops dropped several hundred feet and the sky was clear. My choice of position proved crucial; the extra thirty feet of elevation provided an extra hour of observing, compared to telescopes lower down.
An hour after the end of twilight, a strong south wind developed. It did not bring the fog upslope, so I concluded it was an at-altitude phenomenon. It rapidly blew away the last remnants of moisture at peak level, leaving dark sky and clear conditions for those lucky few with telescopes well stiffened against vibration and sufficient winter woolies to block the wind chill.
I had gotten hold of an 80 mm Vixen refractor, the conventional doublet that Celestron has been selling as the "Premium" version of the FirstScope 80. It seemed to have nice optics -- you expect that from Vixen -- though conditions did not permit a decent star test. Scarcely after sunset, I took a look at the three-day moon at 91x. The terminator was at about 55 degrees east Selenographic longitude, roughly bisecting Mare Crisium and providing an excellent view of what some of us call the "Fabulous Four" of new-Moon craters -- giants Langrenus, Vendelinus, Petavius, and Furnerius, aligned in a neat north/south row south of Mare Crisium. The Moon looks strange with so few dark features visible.
The field of view in the 80 mm was satisfyingly dark, too. At 28x, even without increasing magnification to darken the background glow, I could easily see NGC 4387 and 4388, in the same field as M84 and M86.
I had planned a more elaborate observing program, but wind restricted my ability to carry it out, so I spent most of the evening chasing down Messier objects with the 80 mm. I logged almost 80, everything from the Beehive and M67 clear through the summer Milky Way. Finding and identifying Messier stuff was a cinch with this aperture -- a 32 mm Plossl gave a nice, wide field, and the 28x it provided was sufficient to show detail in many objects. All of the galactic clusters were resolved. The Trifid, Lagoon, Swan, Dumbbell, and Ring showed shape and detail of nebulosity. M94 showed its bright center, the elongate Sombrero revealed its dust lane, and the companion to the Whirlpool was easy. Many of the globular clusters were granular, even at such a low magnification. (Notable exceptions were M54, M55, M69, M70, and M80.)
A moderate focal-length 80 mm refractor is indeed a fine beginner instrument. I hope the Taiwan models that Celestron and Orion are now importing have decent optics -- they are lots cheaper than Japanese units.
There was an unusual amount of interesting equipment at the Peak that night. What a shame that conditions did not let us make better use of it...
A Takahashi 225 mm Schmidt-Cassegrain had recently changed hands; its new owner had it set up for solar observation in the late afternoon. I have looked through this unit before; its optics are excellent, a serious embarrassment to Meade and Celestron alike.
Two observers had just taken delivery of Vixen 102 mm fluorite refractors, from Telescope and Binocular Center. I have looked through both of them; they seem still to have to optical quality which has made Vixen fluorites so much prized in the past, and both owners are extremely pleased.
The new Great Polaris mount has some interesting changes, too. Most are improvements, but not all. First, the mount is more compact -- the distance from the right ascension axis to the telescope end of the declination axis is smaller than on older units. The reduced lever arm reduces vibration and counterweight size. With the tube in certain positions, though, access to the right ascension clamp is cramped, particularly if one is wearing gloves. That's a small problem, but perhaps a longer lever on the clamp would make it easier to use.
Second, the new dual-axis drive is excellent. The motors reverse, and several rates of motion are selectable from the control paddle. The fastest, 32 times sidereal, is sufficient to set the telescope quickly once the object is in the finder field. The new motor arrangement has no provision for clutches or clamps on the motor shafts -- the motors stay engaged, so that manual slow motions cannot be used installed. But the 32x rate is sufficient that owners won't need them. You unclamp the driven gears from the axes, hand slew the telescope till the object is in the finder field, then reclamp, and use the motors to center it up.
The slim and functional control paddle, however, is marred by a serious design flaw. The power-on LED, thoughtfully located between the four control buttons, is vastly too bright, and what's more, it's green! This night-vision-ruining abomination will obnoxiously advertise to all attendees at a star party, that Vixen has messed up thoroughly. I hope the manufacturer has sense enough to fix this one, and soon -- low-intensity red LEDs are plentiful. Meanwhile, black electrical tape is cheap and opaque, and so are those little "lemon" stickers.
Though the head and drive of the new Great Polaris mount are excellent, the tripod is not. What comes with the unit has telescoping aluminum legs, that provide no vibration damping at all -- the unit has the jiggles. This is a stupid mistake, and there's nothing wrong with the tripod that can't be fixed with twelve feet of two-by-four and an axe. (Well, maybe a saw and a drill, too.) ("Two-by-four" is a US lumber plank size that is roughly 4 by 9 cm in cross-section, and no, that's not two by four inches, is it?)
The Great Polaris mountings that Celestron has provided, came with well-made wooden legs that were not only stiffer than the aluminum ones, but also helped considerably to damp vibration. One isn't used to Japan, Incorporated going low-tech on a product for export, but lightweight aluminum tripod legs on an astronomical telescope are certainly a throwback to the stone age. Perhaps some enterprising entrepreneur will offer wooden legs, or maybe a wooden cross-brace, for the aftermarket; meanwhile, purchasers of the new Great Polaris should at the very least get a set of Celestron vibration-damping footpads (see below) to go with their telescope. These help a lot.
Joe and Karin Sunseri, of Earth and Sky Adventure Products, were there with an Intes Micro product that I had not seen before -- a six-inch f/8 refractor, with a doublet objective which allegedly uses wild glasses for both elements, and has substantial aspheric figuring on at least one surface. Conditions did not permit an accurate star test -- diffraction patterns inside and outside focus were visible, but not steady. In any case, the correction for spherical aberration was certainly better than the seeing. In attempting to perform a test, I was struck by how color-free the out-of-focus images of Regulus were -- I could not detect the slightest trace of color anywhere in the pattern, even when looking hard and patiently. Joe said that Intes was advertising this unit as an apochromat, and it might actually be so -- there are combinations of new glasses that permit designers to bring three colors to the same focus; perhaps Intes has used one. I would like to know more about this design, and to see it in better conditions. (Incidentally, fluorite doublets, and both Meade and Tele Vue "ED" doublets, are not apochromats, and what's more nothing in the term "apochromat" guarantees good correction for chromatic aberration.)
The most upsetting equipment not tested was eyepieces. I had my usual eyepiece box, and had remembered to bring my Ramsdens. Joe and Karin brought a full set of Intes monocentrics. Tele Vue designs abounded, as did most of the other common types. One observer has several Takahashi eyepieces, and -- ta da -- there was also present both a full set of Zeiss Abbe orthoscopics and a full set of Pentax orthoscopics (a different product line than the SMC-XLs that Orion sells). We were all allegedly anxious to compare all of these on some demanding object, but between poor seeing, fog, and wind chill, we didn't do it. Waah! I did hear one interesting speculation about the current line of Zeiss eyepieces, which I will pass along for what it may be worth. One fairly knowledgeable person said that it would not be surprising if these units were in fact OEM'd in Japan, for the Zeiss label. As long as they perform, that's fine with me, and the Abbes are indeed highly regarded, but some Zeiss connoisseurs might be mortified.
I packed up a little past midnight, and drove home. It was a good night, notwithstanding the odd weather.
-- Jay Freeman
I did a little experiment with the Celestron vibration-damping footpads. I had heard a lot of hype about these things but I had also heard that they don't help much with the giant Meade tripod. I put in a high power eyepiece and focused on the pole on the top of the Peak. A sharp one-finger tap on the fork arm produced a wiggle that lasted for maybe two seconds before damping out. Then I borrowed a set of the vibration pads from Robin Casady. The same tap now damped out in less than a second! (In fact, I didn't actually time it; the difference was way to obvious to be worth quantifying.) Conclusion: the pads really do do what they're supposed to. If my brain wasn't so cold, maybe I would have thought to check to see if they helped with wind induced vibration, too. We certainly had ample opportunity for that experiment last night! -- Bill Arnett
Last Saturday looked like it would be a great night then at sundown the fog came up just a little above the observering site. It would drop down for a little while then come back up. About 2am the wind started really blowing at least 35mph I would guess. So it was now windy and foggy. It kept blowing until about 8:30am Sunday. Sometime bewteen midnight and 2am raccoons got into the back of my truck and took off with most of my food although by that time I wasn't hungry anyway.
When the fog did drop down the seeing was very poor, maybe 2 arc seconds at best. But even with the poor observing conditions it was a fun night. -- Rich Neuschaefer