quest. Nijboer's 19473 paper derives a formula for _ in terms of Bessel functions for given aberrations. However the problem with just using the formula is that complex variations in the amplitude and phase are difficult to handle. A straightforward nmr_rical integration of the above integral is easy to implement and creates a general purpose capability that can handle central obscurations and "spiders" and non-uniform pupil functions E(x,y,z). It should be noted that the speed of today's

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... ers makes this approach very attractive. The numerical approximation of the diffraction integral, in this case, requires the addition of very large numbers, s, measured in millions of kilometers and very small numbers, Z_, measured in fractions of a wavelength. This mismatch https://ntrs.nasa.gov/search.