Abstract: The present invention is an off-axis collimator used to monitor the optoelectronic performance of a radiometer, which off-axis collimator is comprised of a single off-axis paraboloidal mirror, a broadband radiant energy source housed in an integrating sphere, detectors for monitoring the performance of the broadband radiant energy source, and a housing for the collimator.

Abstract: The improved passive radiation shielding means for radiant coolers as illustrated and described herein involves a device wherein one or more radiation shields having open, externally viewing end areas are positioned in a housing between stages of a radiant cooler. Mechanical low conductive supports hold the various elements, including the device to be cooled, the cooling stages and the radiant shields in place. In one practical embodiment of the device of this invention for use in cooling detector means aboard a satellite, the housing includes first radiant cooler stage is composed of a radiator surface, an optically polished and aluminized cone, two gold plated radiation shields and eight tubular low conductance insulating supports which mount the first stage to the vacuum housing. In addition there is hinged earth shield which may be deployed on command, whether the device is being tested or its in position in orbit.

Abstract: One or more radiant cooler refrigeration stages are coupled to each other in a tandem relationship which in turn are coupled in a tandem relationship with one or more Joule-Thomson cooler stages coupled in tandem relationship with each other.