This is a flight prototype grazing incidence X-ray telescope similar to one that flew on the OSO-IV satellite in October 1967. This telescope, located in the stabilized portion of the craft (the "sail"), was designed to obtain X-ray images of the sun. Incoming photons were focused onto the detector by means of a grazing incidence mirror covered by an aperture, which admitted a thin ring of light. The photoelectric detector included a cesium iodide scintillator and a photomultiplier tube as well as a series of filters. The telescope was designed and built at American Science and Engineering (AS&E) under the direction of Riccardo Giacconi.
This object was donated to NASM by AS&E in 2003.
Gift of American Science & Engineering Incorporated.