3 cup diaphragms
Date1875-1900
Inventory Number2007-1-0356
ClassificationDiaphragm
Subject
Maker
German
?
Maker
American
?
Maker
French
?
Cultural Region
Dimensionstallest: 1.1 × 1.8 × 1.8 cm (7/16 × 11/16 × 11/16 in.)
Material
DescriptionThese are three cylindrical cup diaphragms with different apertures. They have crossed alignment marks on the stopped surface and threads on the interior of the barrel. They are blackened brass.
Signedunsigned
FunctionA diaphragm is a thin opaque structure with an opening (aperture) at its center. In optics, its role is to regulate the passage of light through a lens or optical system. It is sometimes called an "aperture stop" (or just "stop"). It can have an aperture of fixed size or one of adjustable size. A common form of the latter is the iris diaphragm.
E. Hartnack & A. Prazmowski
Date: 1870-1880
Object number: 1998-1-0584a
E. Hartnack & A. Prazmowski
Date: 1870-1880
Object number: 1998-1-0584b
E. Hartnack & A. Prazmowski
Date: circa 1880
Accessories: objectives in green leather box (5): 2, 4, 6, 7, and unmarked; objectives in brown box (2): 2, 3; oculars (5); 1, 2, 3, 4, 5; polarizing eyepiece and substage apparatus; substage condenser; substage cup diaphragms (4); slider with sleeve to hold substage accessories; large bull's eye condenser with stand; aperture-stop rotating wheel; blue filters (3); flat case; case keys (2).
Object number: 1145a
Boston Optical Works
Date: 1868
Accessories: Slide for 4 objects
Object number: 1211
Camille Sébastien Nachet
Date: 1845-1850
Object number: 1081b
