Testing the figure of exotic aspheres can be difficult and can produce uncertain results if done by conventional means. Equally exotic test equipment has been developed to accurately do these measurements, but such equipment can be quite expensive. Documented here is a simple technique for doing these measurements without resorting to complicated test equipment. The basis for this technique is the introduction of a tilt between the piece under test and its test plate. Modeling of this technique has been carried out on a mainframe computer program to verify its validity. Projection of MTF performance has used Optical Research Associates' CODE-V optical design program. Perhaps more useful is the program which has been written for the HP-41 handheld calculator so that raw data may be reduced in near real time in the laboratory environment. This program uses simple algorithms and produces graphic plots on the HP printer, if available. The program code is included as a part of this paper.
Tim Wise, Tim Wise,
"Simple Technique For Testing The Figure Of High Order Aspheric Surfaces", Proc. SPIE 0540, Southwest Conf on Optics '85, (20 November 1985); doi: 10.1117/12.976091; https://doi.org/10.1117/12.976091