Citation
Abstract
A baffle system for the elimination of first-order specular and diffuse reflection of sunlight from the sunshade of a deep-space optical receiver telescope is presented. This baffle system consists of rings of 0.5-cm blades spaced 2.5 cm apart on the walls of 60 hexagonal sunshade tubes that combine to form the telescope sunshade. The shadows cast by the blades, walls, and rims of the tubes prevent all first-order reflections of direct sunlight from reaching the primary mirror of the telescope. A reflection model of the sunshade without baffles is also presented for comparison. Since manufacturers of absorbing surfaces do not measure data near grazing incidence, the reflection properties at anticipated angles of incidence must be characterized. A description of reflection from matte surfaces in terms of bidirectional reflection distribution function (BRDF) is presented along with a discussion of measuring BRDF near grazing incidence.
Details
- Volume
- 42-103
- Published
- November 15, 1990
- Pages
- 110–117
- File Size
- 346.4 KB