Abstract: A spacecraft telescope door (10) adapted for use with remote sensing devices requiring optical and infrared calibration. The door (10) includes a first calibration surface (24) disposed on a first panel (14) for providing a radiant temperature reference for infrared calibrations. A second calibration surface (26) is disposed on a second panel (12) for providing an absolute radiance reference for optical calibrations. A panel hinge (16) controls the relative position of the panels (12,14) with respect to each other, and an aperture hinge (20) controls the relative position of the panels with respect to the aperture (28). In a specific embodiment, the first surface (24) is painted with chemglaze Z306, a highly emissive paint with a low reflectance for facilitating infrared calibration. The second surface (26) is painted with YB71, a diffuse reflective paint for facilitating optical calibration.

Abstract: An image intensifier tube comprising a sealed envelope having therein means for controllably liberating oxygen within the envelope, and an input screen including an oxygen conditioned layer of fluorescent material and an overlying layer of photoemissive material which may be oxidized to improve the photon-to-electron conversion efficiency of the input screen.A method of improving the conversion efficiency of an image intensifier tube input screen including the steps of exposing a layer of fluorescent material to oxygen prior to the deposition of an overlying layer of photoemissive material, and subsequently exposing the layer of photoemissive material to oxygen, if desired, after the tube envelope has been sealed.