To measure the topography of a surface by conventional phase shifting interferometers, exactly known phase shifts between reference and test surface are required. To keep the phase shifts stable during measurement, the interferometers are mounted on vibration isolation tables. To overcome the necessity of expensive vibration isolation equipment, in [1] a low cost interferometer for plane surfaces had been presented that copes with vibration, and makes use of the vibrations to create phase shifts during the measurement. This article describes the extension of this approach to the measurement of spherical surfaces in the presence of vibrations.
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