Variation of energy throughput with off-axis angle for the S056 x-ray telescope

The S056 solar X-ray telescope, a paraboloidal-hyperboloidal Wolter type I instrument, was used in the Skylab solar observatory to photograph the sun in various soft X-ray wavelength bands. It is necessary to know how the energy throughput of the telescope varies as a function of off-axis angle at various wavelengths in order to compare the relative intensities of solar X-ray emission from various areas of the sun captured on the same photographic frame.