A generalized Wolter Type I design for the solar X-ray imager (SXI)

The off-axis aberrations of the classical Welter Type 1 X-ray telescope consisting of a confocal paraboloid and hyperboloid severely limit the useful angular field that can be imaged onto a flat detector. A family of alternative designs based on two hyperboloids has been developed that improves the wide-field imaging performance by aberration balancing. A particular member of this family, designated as H-T#17, has been selected for use in the SXI instrument. The development of the SXI optical prescription and its defining parameters are first presented, then detailed optical performance predictions are compared to those of the SXI baseline design.