Imaging performance of a normal incidence soft x-ray telescope

We have made the first measurements of the imaging performance of a normal incidence soft x-ray telescope at BKα (0.183 keV, 67.6 Å). The performance is quite good; at 1.5°off axis the resolution is about 1 arcsec full width at half-maximum and 50% of the reflected power within 512 arcsec is contained within a diameter of 5 arcsec.