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 48h. 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.
G. R. Hostetter, D. L. Patz, H. A. Hill, and C. A. Zanoni, "Measurements of Scattered Light from Mirrors and Lenses," Appl. Opt. 7, 1383-1385 (1968)