One of my readers made a very good suggestion on how to stiffen up Big Bertha: use steel wire to brace the various parts. The first try wasn't very successful; the guy at Lowe's told me to clamp the ferrules onto the wire with pliers. I used a vise. That didn't work.
So I asked a friend of mine, J. Norman Heath, perhaps the only person who is both a circus rigger a published scholar on the Second Amendment. (Weirder things have happened, but I don't know where.) He gave me some tips--including why using a vise to close a ferrule doesn't work. His blog is here.
The right solution was to go back to Lowe's, and hunt around until I found this swaging tool for crimp these correctly.
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It does rather look like something with which Jack Bauer would torture midgets to get information out of them, doesn't it?
Here you can see the way that the turnbuckles tighten the steel wires, tensioning the system diagonally.
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And no, the mask on the mirror is black--it's just overexposed.
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It still isn't right. I ran out of turnbuckles, and so this is asymmetric. Once these four are tensioned, it moves the optical components enough of alignment that there isn't enough play left in the mirror cell screws to collimate correctly. So I fumbled around a bit, and settled for something that wasn't quite right--but still did okay. (I'll finish this tomorrow.)
Here's a picture of the Moon at prime focus, 1/125th of a second, ASA 100:
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Here's a shot done with eyepiece projection, using an 18mm orthoscopic, 1/45th second at ASA 800:
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It should collimate better tomorrow.
By the way: through the eyepiece looks far better than these pictures.
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