optical flat
Datecirca 1946
Inventory Number2003-1-0152
ClassificationOptical Flat
Subject
Maker
American
?
Cultural Region
Dimensionsglass: 2.1 × 7.5 × 7.5 cm (13/16 × 2 15/16 × 2 15/16 in.)
case: 6 × 15.5 × 15.8 cm (2 3/8 × 6 1/8 × 6 1/4 in.)
case: 6 × 15.5 × 15.8 cm (2 3/8 × 6 1/8 × 6 1/4 in.)
Material
Accessoriescase
DescriptionClear Pyrex cylindrical optical flat in mahogany case. There is a note in the case that says: "#2, 2-3 micro (?) M.C.N. 7-16-46". The corrected side of the test plate is opposite the N.G.F. marking on the plate." Good side of plate is heavily scratched.
Signedunsigned
FunctionThis disk is used to determine optically the flatness of a surface. It is itself made to be extremely flat (within a few millionths of a inch). When put on a surface and monochromatic light is shone on the flat, interference patterns will form. Their analysis determine the flatness of the surface.
Date: 1890-1930
Object number: RS0501
