Improved Design for Stray-Light Reduction with a Hemispherical Imager

Center for Astrophysics and Space Sciences, UCSD, La Jolla, CA 92093-0424, U.S.A.

Abstract
We present a significant design improvement over previous visible-light stray-background-reducing baffles suitable for use on a stabilized deep-space platform. In earlier research we showed that when background-light sources are confined to a hemisphere or less, a conventional labyrinth baffle can be replaced by an array of concentric vanes, oriented away from the desired field of view. This configuration delivers substantial savings in size and weight. The present improvement replaces the concentric vanes by a smooth curved surface. This permits simplified fabrication and handling, provides even more weight reduction, and delivers improved performance for a given size. Laboratory measurements confirm stray-light performance with 10^-14 rejection viewing as close as 3 to a bright-light source.