Junkbox Telescope Gallery
Some years back I posted Jeff Duntemann's Homebrew Radio Gallery, and for reasons unclear it's become one of the most popular pages on my site. (Tube construction may not be quite dead...) So a while back I wrote up and (almost) finished a page about all the various telescopes I've built ( Read more... )
The dobs I've used were underweight and very wobbly. This may mean they were badly built (both were home-made) or badly sited, but they left a very bad impression. When set up correctly, my 10" is solid as a rock, but it weighs 400 pounds and I'm having increasing trouble moving it around as I get older.
I also prefer to move only one axis to follow an object as the Earth turns. Never tried a Poncet table, which would certainly be one solution to the problem, though tricky with the kind of scope I have. Altazimuths make me nuts.
And although it may seem (at a conference or star party) as though a lot of people are building scopes these days, there was a time when lots of my friends were doing it--it seemed, like ham radio, to be something most young geeks gave a shot at sooner or later. Now no one in my near circle is, coverage in S&T (remember Gleanings?) is rare, and the mirrors themselves are a lot harder to find than they were 25 or 30 years ago. This doesn't bode well for the hobby.
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My 15" f/4.5 has an eyepiece that's precisely at standing eye level for me at the zenith (which is why I chose that size/speed mirror). It weighs about 65 pounds total, the heaviest single part is about 30 pounds, I can break it down and have it in a minivan in about 5 minutes, set it up in 8 to 10 and collimate it in 3 when I get there, move it around trivially due to wheelbarrow handles and pneumatic wheels, I can view and track manually at 400x in 20 MPH winds with virtually no shake. It steadies after a tap in a second.
Tracking is pretty trivial and honestly I don't even consciously think about it anymore. With crappy alt-az mounts, yes, it really bites. But with a properly adjusted teflon-bearing dob, the scope pretty much reads your mind. You put your hand on the end of the scope, and when you think about moving it, you almost unconsciously move it. There are no balance problems even when I switch from a 1.25" 10mm eyepiece to a 32mm Nagler. I even tried a 55mm SWA plugged into a Paracorr once and the balance was still pretty good.
Yes, I've used pretty bad dobs in the past. I've also used eq mounts that were completely abysmal and useless.
I don't subscribe to S&T anymore. Check out "Amateur Astronomy." It's a b&w magazine that was founded by the guy who founded the Chiefland, Florida astronomical community. He built his own 36" scope and TRAVELLED with it. He spent 6 months a year on the road going to star parties. He's handed off the reigns now, but the new guy seems really good too.
S&T has decided that doing equipment reviews, cosmology articles, a sky map and some appendices (jovian satellite tracks, etc) and following professional astronomy and space missions is the ticket. Unfortunately for them, those are pretty much exactly the things that print media can't hope to compete with the web on.
I'd say people not making their own scopes doesn't bode well for the hobby of scope making. I'd say that it's as unimportant to the hobby of amateur astronomy as not soldering up your own Altair is to programming. OK, the programmers may not be hooking resistors and an op-amp and speaker up to a parallel port and using it to make music, and there's something a little sad in the loss of that level of hacking, but there is still plenty of very creative stuff going on, and at levels that people wouldn't have dreamed of 10 years ago.
There are some amateur comet hunting programs out there that use homebrew drift cameras hooked to data analyzing systems via the internet that are amazing. And there are plenty of other examples. Amateurs have always made contributions to the field, and if anything that's increasing.
What really kills astronomy is light pollution. It's hard to develop a sense of wonder for the skies (or maybe even in your soul) when you go through childhood without ever having really seen the stars. I think the world would be a lot better place if everyone got the chance to lie back on the ground on a summers night in a place where they can see a few thousand stars, and just look, a couple of times a year when they were children. It's one of the saddest things I can think of in the modern world.
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If I may cut in, I have to agree with the point you made. It's true, people don't do the kind of Heathkit hobbycrafting you describe. Mr Duntemann has mentioned writing hex code by hand; nowadays hex editors are commonplace. I once worked out the orbital dynamics of a fictional gas giant and its moons using paper, pencil, time and a TI-30 - nowadays there are applets online that will calculate orbits.
The point is that soldering components by hand, hex code by hand and pages of scribbled notes and numbers are primitive arrangements. No, “new and improved” are not always synonyms - but once upon a time, operating an automobile was so complex a task that a chauffeur was necessary, possessing the same idiosyncratic knowledge of the motorcar as a livery hostler knows of horses. Today your teenage daughter hops in, starts it up and drives off without a thought. (Some people never even open the hood.)
So, your backyard hobbyist of today does not grind his own mirrors. What the heck, he never smelted the glass either. Where you do have a point is in these newfangled computer gizmos controlling the telescope. When it finds M31 on command, and you rely on it to do so, how well do you learn the night sky? All you learn is keypunch skill.
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http://miastro.com/atm/index.html
I no longer use a digital setting circle, I didn't like it. I found that I prefer to star-hop, even if it takes me a half hour to find something.
I've also added a University Optics 8x50 finder with an Amici prism, and switched to a Telrad reflex finder.
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