Sensitive Parallax Detector for Optical Bench

Abstract

IN accurate measurements of focal-lengths and the like, on an optical bench, it is customary to employ the points of pins mounted on adjustable stands. The lens under test has itself to be so mounted as to enable it and the pin-points to be ‘lined up’ parallel to the tracks of the optical bench. This is a somewhat troublesome and time-consuming operation, and distracts the students' attention from the basic aim of the experiment. The device herein described eliminates much of this tedious procedure and can indeed yield more accurate settings than the older procedure. As it is easily adaptable to any type of optical bench, I will confine myself to describing the details peculiar to the device itself.