Measurements of Scattered Light from Mirrors and Lenses

Abstract

The limitations arising from scattered light from lenses and mirrors in a program of daytime astrometry near the sun are discussed. Measurements were made of the angular distribution of the scattered radiance for (1) a coronagraphic lens, (2) a 2.54-cm thick coronagraph quality window, and (3) flat quartz mirrors. Results are also given for the optical elements after they have been exposed in a vacuum for 48 h. The results indicate that the accuracy of a daytime astrometry program would be determined by the shot noise of the scattered light produced by the refracting elements and the sky, each producing equal contributions.