I'm reading King's History of the Telescope with great interest.
It would seem that suitable blanks of reliable quality, in sufficient quantity, is integral to the history of the refractor, in the same way that the struggle for a durable reflective coating is integral to the history of the reflector. And it is a problem that for refractors apparently has never had as satisfactory a resolution as for reflectors, to judge from comments from some of the pros here and elsewhere.
I find it amazing that Yuri or Roland can't be 100% confident of getting good glass to whatever specs at say no more than a 2% or 5% rejection rate.
I guess in the early days they didn't know *how* to do it. These days the *production scales* don't permit it...?
regards
Greg N
It would seem that suitable blanks of reliable quality, in sufficient quantity, is integral to the history of the refractor, in the same way that the struggle for a durable reflective coating is integral to the history of the reflector. And it is a problem that for refractors apparently has never had as satisfactory a resolution as for reflectors, to judge from comments from some of the pros here and elsewhere.
I find it amazing that Yuri or Roland can't be 100% confident of getting good glass to whatever specs at say no more than a 2% or 5% rejection rate.
I guess in the early days they didn't know *how* to do it. These days the *production scales* don't permit it...?
regards
Greg N
"Scope will get you through times of no money better than money will get you through times of no scope." --Freewheelin' Franklin
