Measurement of total hemispherical emissivity of contaminated mirror surfacesThe effects of dust contamination on the total hemispherical emissivity (THE) of a 1.5-inch-diameter Al/MgF2-coated telescope mirror are investigated experimentally. The THE is determined by means of cooling-rate measurements in the temperature range 10-14.5 C in a vacuum of 100 ntorr or better. Photographs and drawings of the experimental setup are provided, and results for 11 dust levels are presented in tables and graphs. It is shown that dust has a significant effect on THE, but the experimental losses are only about half those predicted for perfectly black dust in perfect thermal contact with the mirror surface.
Document ID
19890054160
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Facey, T. A. (Perkin-Elmer Corp. Danbury, CT, United States)
Nonnenmacher, A. L. (Perkin-Elmer Corp. Space Science Div., Danbury, CT, United States)
Date Acquired
August 14, 2013
Publication Date
January 1, 1989
Subject Category
Optics
Meeting Information
Meeting: Stray Light and Contamination in Optical Systems