Quote:
Originally Posted by mental4astro
My idea is to incorporate the Sonotube section containing the mirror and float into where Albert has his "fibreglass" tube, and add some more bracing for the alt bearings.
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Hi
Sonotubes were part of the reason big dobs had a lousy reputation for soft images in the early to mid eighties. Thin aluminum sheet or 1 to 1.5mm Aircraft Ply is much better thermally
I know a fellow who built a very good 18" F4.5 version/rendition of the Highstone scope , and only got it stabilised to his satisfaction with fine wire guy ropes to tension it up. He said he would build a standard truss next time around. I think they are fine for a 12" but pushing things with an 18"
Mark