Ask any refractor manufacturers out here and there if they can make
such precision in 5" objective for... about $200 (dealer's profit included).
Ask them if they can support such quality in general.

I think, that they will only smile in answer.


Valery Deryuzhin.







Is that 200 dollars of USA labor rates or starving chinese peasant labor rates?

A western paid optician could probably only spend a few hours getting a good,
smooth spherical surface.....a chinese peasant could spend a WEEK or 2 on
it...and you can be a peasant and STILL be a skilled optician .....at least in
some ways....

You ASKED about possible accuracy....my answer being that 1/20th wave refractor
wavefronts ARE ALOT easier to obtain than 1/20 wave reflecting wavefronts....

labor/cost is a whole other can of worms...

take care

Blll