Making corrector plates by Schmidt's vacuum method.
The theory and procedure are given for figuring corrector plates for Schmidt cameras and related systems following Bernhard Schmidt's classic method. The figure is achieved while the plate is deformed with a partial vacuum on one side. The method easily yields zone-free plates. A modification is described here wherein the correct profile is obtained without precise knowledge of the Young's modulus or Poisson ratio of the particular glass disk in hand. The method is recommended for systems of f/2.5 or slower as there is danger of the plate breaking for faster systems.
Everhart
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Itek Corporation, Lexington, Massachusetts 02173, USA.