The Celestial Tourist Speaks
Jay Reynolds Freeman
If anyone does not believe that California had an uncommonly bad winter, consider the awful truth: I bought an Astro-Physics refractor in early December, 1998, and did not have first light until April.
High-end telescopes tend to change hands in lock-step whenever somebody buys a new one. A friend had ordered a 155 mm f/7 EDF from Astro-Physics when the company last took orders, and mentioned to several people that he would probably sell his old big refractor when the new unit arrived. I was the first person to express definite interest in the used instrument, and I continued to whine and whimper at regular intervals during the ensuing months, so I ended up getting the telescope. I have been trying to sell my own "old" instrument - a Meade 127 ED - but with no luck so far.
My new acquisition is the optical tube assembly for a 1987 model Astro-Physics 6-inch f/8 triplet refractor. It came with an assortment of tube rings and associated hardware, a right-angle finder, an electric focuser - which I promptly removed - and a simple wooden carrying case, which resembles either a weapons carrier for an anti-tank missile or a coffin for the cruelly murdered body of a half-starved and emaciated nine-year-old child.
Buying things from friends makes for weird pricing. The prior owner originally asked $1750 for the telescope, but I protested that that wasn't nearly enough. We settled on $2000, an amount which he thought too high and I too low. Yet our complaints were of roughly the same volume, so I suspect the price was fair.
I took it home and the rains began. Oh, there were two good nights between December and April, but I was anxious to carry on with my primary observing program, chasing down faint fuzzies with Harvey, my Celestron 14, so I kept putting off using the big refractor till a first-quarter Moon night, and never got one. The San Jose Astronomical Association's in-town public star party, at Houge Park in San Jose, California, on the night of Friday 23 April, finally provided a chance.
Carrying a big refractor in a Geo Metro is an interesting exercise in packing. The case is far too long to fit in the cargo area, even with the rear seats folded forward, so I ended up reclining the front seat as far as it would go, and loading the wooden container stiffly on top of it, much as if it were a very nervous passenger, trying to lean back and relax, and failing miserably. In that position it was clearly visible from the outside, so that every passing police officer could decide whether I was carrying a body or a bazooka. Fortunately, my Losmandy G-11 mount and my other observing gear all pack quite compactly, and I had plenty of bungee cords to hold the case in place, so I managed, but even so, hauling the new refractor is a lot more hassle than hauling my C-14.
Setup was fairly quick. I have the pier extension for the Losmandy, which put the dovetail clamp pretty high, but the six-inch's tube is an easy lift. I had put it into the box with tube rings and dovetail plate attached, and it was no trouble to pick it up, slide it into position, and fasten it in place. I didn't actually think to weigh the tube, but I needed only one 10-Kg (22 pound) counterweight for the mounting, and it was further out than the telescope.
I used Venus to line up the finder, and happily noted through the main eyepiece that there was surprisingly little color visible. The newer Astro-Physics refractors have no color that I can detect, and this one isn't quite that good, but it has far less color than does my smaller and slightly slower Meade 127 ED doublet. A look at Sirius at 248x confirmed the good color correction, though seeing at its relatively low elevation was not up to doing a star test to check on spherical aberration.
Then I looked at the Moon, which was much higher in the sky and had better seeing. My 248x eyepiece - a new Pentax 5 mm SMC ED Orthoscopic - gave a little too much magnification, so I dropped back to an 8 mm Brandon and 155x. The view was wonderful. The terminator was past the Straight Wall and Birt, but I am not much of a lunar observer and had not happened to have seen the Straight Wall in such shallow illumination before, and so did not immediately recognize it. Rima Birt was prominent.
I moved north to the Alpine Valley, where persistent observation yielded no more than an occasional hint of the central rille - not enough to log - then dropped back to Archimedes and the Hadley area of the Apennines. I could see several rilles in the system that extends from Archimedes toward the Apennines, and had a particularly nice view of Rima Hadley, not only the portion that runs parallel to the Apennine front, but also the portion at nearly right angles to it, that passes close by the Apollo 15 landing site. This is one of my favorite areas on the Moon, for through a decent-sized amateur telescope I can identify features and vistas that I have seen via live video from the lunar surface, as the astronauts operated their camera. The view through the six-inch was almost the equal of one I once had through my C-14, the difference being that the six-inch did not show the crater that nearly bridges the rille where it turns outbound from the mountains - I think that crater is sometimes called Hadley C.
I spent a fair amount of time showing this view to members of the general public who showed up for the star party, and to other telescope operators. Most everyone thought it was wonderful. A few lunar and planetary enthusiasts, who did not have similarly-sized refractors, told me how sad it was that my new telescope had terrible optics, and hinted that if I wanted to reclaim my investment, they would be willing to take it off my hands, perhaps even for the price I had paid for it.
Mars was lower in the sky, and was disappointing, not only because of its position but also because the seeing deteriorated slightly as the night wore on. The central meridian was at about 230 degrees. At 155x, in good moments, I could see the Hellas Basin just coming around the limb, much dark area surrounding it, though sufficiently foreshortened not to show any structure, the north polar cap, and a more nearly central small darkish area, evidently Trivium Charontis. That's not too shabby for the conditions.
I spent a little while Messier hunting - no easy task under the Moon and city lights. Nevertheless, at 78x (16 mm Brandon) I found and easily resolved most of the winter-sky galactic clusters. I looked at a few wide double stars, too, but never did think to try a star test.
So at the end of the first night out, I am well pleased with my new telescope. The 1987 Astro-Physics 6-inch f/8 shows every promise of being exactly what I expected; namely, a high-quality triplet refractor with immaculate optics, well-suited among moderate apertures for spectacular lunar and planetary views.
Nevertheless, some among you may be wondering why I bought it in the first place. Don't I have a Celestron 14, and don't I always say that aperture wins? Haven't I often said that it appears to me as if even high-end six- and seven-inch refractors are routinely outperformed not only by my C-14 but also by humungeous but transportable Dobson-mounted Newtonians? Isn't it a little odd to buy a telescope which is lower in performance and more cumbersome to transport than one I already own?
Well, yes, yes, yes, and yes. With respect to the third question, I reiterate that I have compared six- and seven-inch refractors to the other telescopes mentioned on numerous occasions, and have yet to see circumstances when I preferred the view through the smaller instrument. (I should also hasten to add that many other observers who were present on those various occasions do not agree with me.)
I bought the telescope for several reasons. First, I like telescopes, and I enjoy having different kinds to play with. Second, I like quality in my toys, and the Astro-Physics refractors with which I have been familiar deliver that commodity in large lots. Third, I wish to investigate more carefully the issue of relative performance between high-end refractors and some of the other telescopes I have mentioned, and it will help to own this one, even though I can neither transport nor mount both it and my C-14 at the same time.
The apparent awkwardness of size may diminish as I acquire more experience with the telescope. Even if it does not, there is probably a larger telescope transporter than a Geo Metro in my future. At that point, the big refractor will make an excellent telescope for public star parties, and for occasions where I do not wish to wrestle with the 23 Kg (52 pound) tube assembly of my C-14.
And there is another reason. I have thought of a wonderful color scheme for a fair-sized refractor. Just don't anybody tell Roland what it is...
|Jay Freeman; last updated: October 03, 2007||Prev Next|