DESIGN OF OPTIMUM CODED MASK X-RAY TELESCOPES

Coded mask X-ray telescopes provide a means of imaging the sky at higher energy than is possible using grazing incidence reflection optics. The results obtained during the first successful flight of a telescope based on this principle have recently been published. To assist both in the interpretation of the results and in the future use of this technique the special considerations involved in the design and operation of this type of telescope are discussed with an emphasis on practical aspects. Whilst mask patterns based on a particular form of cyclic difference set are always likely to give the optimum results, the best telescope geometry depends on the constraints imposed. For these mask patterns the image may be reconstructed rapidly by using a Fast Hadamard Transform. The number of map points in the reconstructed image may be large and care must be exercised in judging the statistical significance of peaks observed. © 1979 Royal Astronomical Society.