Diffraction patterns formed by an off-axis paraboloid surface

We derive a general, closed-form expression for the diffraction patterns including the aberrations that are due to off-axis alignment and positioning similar to, of a paraboloid mirror. The diffraction patterns obtained in the focal plane of an off-axis paraboloidal mirror suffer modifications by the aberrations that are inherent in these surfaces: astigmatism and coma. Different magnifications in two perpendicular spatial directions indicate astigmatism. The Airy function, which affects a single spatial coordinate, describes the coma aberration. We identified the coma by the increased number of intensity zeros within adjacent lobules. (C) 2001 Optical Society of America.