1 December 1978 Design With Two-Axis Aspheric Surfaces
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Abstract
An unusual type of surface that has been found to be very useful in the design of certain kinds of unobscured telescopes is described. This surface has an aspheric deformation which is the superposition of two separate conventional aspherics with axes that are shifted relative to one another. For example, a parabolic departure from a sphere might be super-imposed on top of a conventional parabola but with the axis of the superimposed deformation displaced laterally from the axis of the base parabola. Another example might be an aspheric deformation added to a sphere but with the axis of the deformation not going through the center of curvature of the base sphere. Such surfaces allow the designer to optimize unobscured telescope configuration types that otherwise are very difficult to handle. In particular, the use of these surfaces allows the designer to avoid coming to grips with a full Zernike set of aspheric terms, which are very expensive to use in optimization and usually contain a lot of excess variables that are not really needed. The two-axis aspherics only have terms relevant to the design tasks for which they are best suited, and make the design task simpler and more efficient. The way in which these surfaces are set up in the Perkin-Elmer design program is described and several design examples which feature these surfaces are given.
© (1978) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
David Shafer, "Design With Two-Axis Aspheric Surfaces", Proc. SPIE 0147, Computer-Aided Optical Design, (1 December 1978); doi: 10.1117/12.956638; https://doi.org/10.1117/12.956638
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