Improved Coatings For Large Astronomical Telescope Mirrors

Abstract

Coatings with lower emissivity than the traditional aluminum coating are required for large telescope mirrors. Multilayer coatings consisting of silver with ultraviolet boosting overlayers and copper underlayers for increased environmental resistance have been proposed. These multilayers are examined briefly, and some of their implications for the coating of large astronomical telescope mirrors are considered. A major problem is that they demand much greater uniformity than simple metallizing. A possible coating plant layout is suggested.