A radial grating dividing engine of high accuracy

Abstract

A dividing engine for the production of radial gratings by photographic means has been constructed according to the principles described by Burch. A moiré fringe signal derived from an existing pair of radial gratings is used to control the manufacture of a similar but improved grating. Repetition of this process has led to the production of a second generation of gratings with a peak-to-peak error less than 0.2 second of arc.