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X-Ray Imaging Telescope On EXOSAT

The European X-ray observatory EXOSAT, to be launched in 1981, will carry two Wolter I type X-ray telescopes, each having a geometric area of about 100 cm2. Due to severe mass constraint of only 7 kg per mirror assembly, imposed by the spacecraft, an epoxy replication technique has been used for the mirror fabrication. A description is given of the manuacturing techniques employed to produce the glass master, the beryllium substrate and the final replica mirror shells. Special measurement and control techniques were used during the replica optics manufacturing. These techniques and same of the results are discussed. Finally a description of the integration and alignment procedure and performance figures in optical light are also given.