optical flat
Datecirca 1934
Inventory Number2003-1-0153
ClassificationOptical Flat
Subject
Maker
American
Cultural Region
Dimensionsflat: 26 × 26 cm (10 1/4 × 10 1/4 in.)
case: 14 × 29 × 29 cm (5 1/2 × 11 7/16 × 11 7/16 in.)
case: 14 × 29 × 29 cm (5 1/2 × 11 7/16 × 11 7/16 in.)
Material
DescriptionOptical flat in round wood box. There is a note under the flat inside the case. According to the latter (see image), it appears to be a homemade flat tested against a 1/20 Bureau of Standards flat in July 1934.
Signedunsigned
FunctionThis quartz 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.
American
Date: circa 1950
Object number: 1997-1-1644
Boston Optical Works
Date: circa 1870
Accessories: 3 Tolles objectives: 1 with 3 fronts; empty can 8/10; 5 Tolles oculars 34 mm dia.: 2 all solid, 2 solid field l. & single eye lens, 1 std.; blue filter; case; key. Also see 1016a: microscope with centerable condenser with diaphragm wheel; and mechanical stage. 1016c: side illumination prism. 1016d, e, f: specialized Tolles objectives.
Object number: 1016b
Sylvania
Date: late 19th-early 20th Century
Object number: RS0368