: Is that the piece of glass from (?)Texas that the guy had from some cloud viewer? The F1 is a real short FL and about all that you can do besides a Schmidt camera (not a bad idea) is to make a Schmidt Cass with it or a Pressmann-Carmichel which is a pretty narrow field instrument. I think that you would be best off looking at the various Schmidt camera ideas as some of them don't use a corrector plate. You might want to get the book Telescope Optics Evaluation and Design ($25) from Willmann-Bell and spend the additional $25 for the software that goes with the book. It runs in DOS and isn't designed for automatic design but it is very helpfull in teaching you about the various tradeoffs in telescope design. : The alternative is to use the glass as a piece of glass for a longer FL scope.

Nope, it is from "I don't have a clue" he he he

it was from a radical idea that I had many years ago, and had way too much spare time to play with it.. but if you can belive it,, it is the front,, now don't laugh the front of an very OLD!!! TV Tube!!

I have no idea as the type of glass,, but all I know it holds that sphere perfectly. it is just strange it is 18" dia F1,, but it is only 3/4 thick!

but not like a normal mirror it is 3/4 thick wverywhere..

like a meniscus(sp) lens.. weird huh.. there has to be something to be done with this he he

Joe