Investigation of the possibility of building large light-weight metal mirrors for the long-wave IR spectrum

Vitrichenko, E. A.; Evseev, O. A.; Isaev, V. I.; Lapshin, V. I.; Leonov, V. N.

Optiko Mekhanicheskaia Promyshlennost, 52, 1985, 13-16.

Abstract The possibility of fabricating a light-weight main telescope mirror from a specially chosen aluminum alloy is investigated. The construction for such a mirror was developed, and two samples were fabricated and tested. A factor of 10 decrease in weight was achieved; a spherical surface having an aperture D/f-prime = 1/2 and an rms deviation of 0.65 microns was fabricated in 120 hours of machining time. The mirror shape remained stable for a least a month.