Design of grazing-incidence X-ray telescopes. I.

The theoretical and practical constraints on designs of grazing-incidence X-ray telescopes are discussed. It is shown that there is a maximum useful diameter for an X-ray telescope. It is further shown that when practical constraints are considered, the maximum reflecting area is not necessarily achieved by utilizing the largest available area within this diameter. Equations are derived that allow rapid calculation of the effective area of an X-ray telescope before one proceeds to detailed studies utilizing Monte Carlo techniques.