University Lowbrow Astronomers

Telescope Shopping.

by Tom Ryan
Printed in Reflections: September, 2006.

I work as an optical engineer at a number of companies and, like a doctor at a party, I get asked about odd, personal optical problems by the people who work there. Some of the questions are fairly normal (Q. “My shaving mirror gives me a double image when I shave. Would a first-surface mirror be sharper, and if so, where can I get one?” A. “Yes, it would be sharper. You can get one either out of some kinds of old overhead projectors, or you can use one of those large rectangular, adjustable side view mirrors from a truck. They’re not really front surface, but they work as if they were.”). Some are unusual (Q. “I bought a security camera to look through a hole in a wall, but it won’t focus close up. How can I fix this?” A. “Buy a one-diopter positive lens from a camera store, tape it to the front of the security camera lens, and never tell me what this is used for.”). But most of them are about telescopes, as in, Do you own one? and What kind should I buy?

Recently, while I was at one of the companies, a mechanical engineer dropped in to the office the company lets me use for their work and asked me the doctor question.

“Tom. You know about telescopes. I was at Costco yesterday and I saw a really big telescope. It had a big lens on it.” He showed me how big the lens was by making a circle with his fingertips. “Do you know if this telescope can take pictures? It is really cheap. $250.00. My wife says I can buy it.”

Now, I’ve met his wife. She is smart, attractive, and very nice. I don’t think either he or she would be satisfied by a department store refractor, so I bit the bullet and decided to help educate him in what is available in telescopes today.

Not that I really know. I haven’t seriously considered buying a telescope for several years. Well, I bought an 8” orange-tube Celestron because I needed a telescope for a project I was working on, and I bought an 8” reflector from Nathan, because he recommended it, but I haven’t considered buying one from a store. I just don’t observe much anymore, although I used to. I stopped when I found that when I looked through a telescope, instead of seeing planets or stars or nebula, I just saw aberrations in the optical system. This is difficult for a man whose religion is light. Since that time, I’ve treated telescopes like women at parties; Lovely to look at, delightful to hold, but if you use it, consider it sold.

Now, given the fact that time marches on and things change in the process, that telescope at Costco might have been fine, much better than the ones available when I was a teenager. Physics, however, doesn’t change much at our level, and if my friend, the mechanical engineer, wanted to take pictures of lots of stuff, he probably would want an 8” telescope.

The next time I headed over to that company, I loaded up the car with the Celestron, the 8” reflector, and some eyepieces, so he could do a comparison. I had recommended that he and his wife visit Peach Mountain during an Open House to see what the club members used and liked, but Michigan skies were not cooperating with that plan. We set up the telescopes in front of the company’s entrance, where we had a good view across the parking lots, all the way down to the horizon and to the buildings in downtown Ann Arbor.

I put a 24mm Brandon eyepiece in the Celestron, and let him look at some distant tree branches. He asked how a camera could be connected to the scope, how the focusing worked, and why was the image upside down? The last question surprised me, because, while the image really was upside down, I had stopped noticing that years ago. Then I put a 9mm Burgess/TMB eyepiece in the Celestron C-8, secretly proud of the fact that a 9mm eyepiece could have so much eye relief because of its clever optical design.

“This image is much darker. I think the other eyepiece is brighter. The other eyepiece was much better.”

I stared at the Brandon wordlessly. He was obviously looking at this whole process very differently than I was. But, he was the one who knew what he wanted.

“Well. Maybe it is better.”

He looked at the 8” Newtonian, and wanted to know why the telescope was less powerful, when it was much bigger that the Schmidt-Cassegrain Celestron. This led to an explanation of folded optical paths, light convergence cones, and other such things, which probably made only a slight impression on him, fortunately.

Finally, we got around to a discussion of what I think are the really important things; quality, price, and portability. Quality must be verified personally for any scope, the C-8 costs more, and it is more portable, and therefore more useable.

“What about GoTo? That’s important, isn’t it? Can your telescope be fitted with a GoTo system? It’s just motors, right?”

He had noticed that the C-8 had an electrical plug on it for the sidereal drive, a retrofitted Astromaster taped to the fork arms, and aftermarket encoders. Being a mechanical engineer, he knew that motors could be fitted to just about anything (including can openers, which, personally, amazes me). He also had a healthier respect for what is reasonable and possible than I do, so when I told him that a GoTo scope had to be purchased with the system already installed by the factory, he accepted that.

He still was confused by a lot of things, and I was having a hard time getting to a point where I told him as much as he needed to know, but not too much to absorb. Why is the field upside down? Why is one eyepiece brighter than another? There are answers to these questions, but I can’t supply them, along with an overview of the market, in 45 minutes. I sometimes run into this same problem when talking to engineers in their 20’s about why it might be a bad idea to use Teflon to support lenses, or why it is a bad precedent to deny access to lawyers to people accused of crimes. It takes time to fully understand some things, and as Poul Anderson said, you can’t ripen a field before its time.

At this point, I was feeling completely inadequate to the task of filling him in on the details of what might be important to him, so it was time for professional help; a trip to Riders Hobby and Mark Rotenberg.

We got in the engineer’s car and drove over to Rider’s. Mark wasn’t there, but a salesperson named Brent helped us out. He gave my friend an excellent overview of the scopes available, what their features were, and what they cost. Unfortunately, Rider’s didn’t have as great a selection as they did a year ago. Brent explained that Celestron and Meade were having trouble keeping up with orders while maintaining quality (would anyone else like to move production to China?), but they should have some more scopes in by September.

Rider’s did have some small telescopes. They had a three or four inch reflector on an equatorial mount, which was so wobbly it scared me, but did serve as an interesting example, and they had a nice 6” Dobsonian. The Dob had a readout system on it. I had been telling the engineer that he could get an older 8” Schmidt-Cass for about $500, tripod and all, and retrofit it with one of these readouts for another $500. That didn’t seem like such a good deal to my friend, even when Brent pointed out that the readout wasn’t $500, it was $125. My friend wanted a GoTo system. He wanted the scope to move under his command, and who can blame him? I have often thought that motorizing inanimate objects is the male equivalent to a woman’s desire for children. I personally think kids are fun, but a robot, now, that’s something!

We looked at pictures of the scopes that Brent would be getting in later, and Brent recommended that we take a short drive over to Rider’s Livonia store, and talk to John Kirchhoff, the store manager. John knew more about telescopes than anyone in the Rider’s chain, and he wouldn’t carry a telescope if he thought it wasn’t any good. Brent also said that the Livonia store sold more telescopes than any other store in the Midwest, which amazed my friend, and me, too, actually.

“It’s so cloudy here. Why would so many people buy telescopes?” my friend asked. “I don’t know”, I replied, but I think it’s like Audrey Hepburn. Being unobtainable just makes you want it more.

My friend praised the staff of Rider’s as we got back into the car. I don’t know what he will decide to buy, or when, but at least I hope I helped him avoid the department store telescope.

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This page originally appeared in Reflections of the University Lowbrow Astronomers (the club newsletter).
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