Abstract: A mirror--typically of the spherical or aspherical variety--is replicated on a large scale (in the order of 2'.times.4') to an optical accuracy in the range of less than one arc minute. An optical master is created by heat shrinking and holding an acrylic sheet to a steel substrate of the same shape as desired mirror in the constant presence of a vacuum at the steel-acrylic interface. The acrylic is optically polished to complete the master. The master is then appropriately dammed to the mirror dimension and poured with subsequently cured epoxy so that the epoxy forms the optical surface of the replicated mirror. A backing master--created by substantially the same process as the optical master--allows fabrication of a backing, composed of a series of adhesive layers typically sandwiching a core material such as commercial honeycomb therebetween, to be made with a curvature substantially similar to the curvature of the replicated optical surface.

Abstract: A large scale mirror is replicated to an optical accuracy in the range of 1 arc minute. An optical master is created by annealing an acrylic liner sheet to a steel substrate in the constant presence of a vacuum. The acrylic is optically polished to complete the master. An epoxy layer is formed on the master. A rigid substrate such as a honeycomb sandwich is provided with a surface closely approximating the contour of the epoxy layer. The substrate is placed over the epoxy layer with a small generally uniform interstice therebetween. Elastomeric material is gently introduced into the interstice while avoiding any stresses, and subsequently cured. Backing irregularity print-through is avoided. Thereafter, the rigid assembly is separated from the master by flexing the acrylic liner.