View Single Post
  #46  
Old 13-02-2020, 09:00 PM
multiweb's Avatar
multiweb (Marc)
ze frogginator

multiweb is offline
 
Join Date: Oct 2007
Location: Sydney
Posts: 22,080
Quote:
Originally Posted by gary View Post
As I understand it, to fabricate a segment, the clever part was to polish
a blank as a sphere whilst applying specific differing forces around the
edge of the glass. Apparently polishing a sphere is relatively easy
Ha ok. Sounds like what Celestron was doing to mass produce their corrector plates. They had a few bases machined with an inverse profile that had the corrector shape then vacuum the glass on top of it, polish it flat then when released the flat machined face would take the right shape.

https://patents.google.com/patent/US3889431A/en
Reply With Quote