Prismatic Lens

2-2-085

An assembly consisting of a bullseye together with concentric dioptric and (sometimes) catadioptric rings, the foci of which are coincident with, or lie within the boundaries of, the source, when correctly focused (in sense 2 of 2-2-155).

Please note that this is the term as it stands in the original IALA Dictionary edition (1970-1989)

English