|
George Levanis (in Newcastle) was thinking of doing one several years ago (using a pre-sagged ultrathin blank).
Not sure if he ever got that project going , as he was still tinkering with his 32" dob with an ultra thin mirror , I think he had issues with his mirror flotation at the time.
I think a dob or newt that big warrants folded optics with a big seconday and a tertiary (diagonal) mirror , or a cassegrain optical configuration , to bring the focus to a level that is easily accessible w/out a ladder , or going to a fulltime prime focus CCD imaging arrangement , doing away with a focusor entirely.
Try Newport Glassworks in the USA for your blank if you go ahead, they'll do fine and precision annealed blanks , and preradiused blanks , and sagged blanks most any size up to about 50" I hear.
|