A radially shearing interferometer including a beam splitter configured to form two optical beams from entering light, the optical beam including a magnified beam and a demagnified beam; a plurality of mirrors arranged so as to generate the magnified and demagnified beams and provide a common optical path with the beams traversing the plurality of mirrors in the opposite direction back to the beam splitter, the plurality of mirrors including a pair of parabolic mirrors, the first of the pair configured to receive one of the magnified and demagnified beams, and reflect the first received beam to a flat mirror configured to reflect the first received beam to the other of the pair. An imaging device may be positioned at a pupil plane of the magnified beam and the demagnified beam so as to record the interference of both beams. A method for recording an interferogram is also disclosed.