Patent ID: 6839143

Claim:
A method for the interferometric measurement of non-rotationally symmetric wavefront errors on a specimen capable of being brought into a plurality of rotational positions, the method comprising the steps of determining at least one measurement result in each of the rotational positions, and carrying out a concluding mathematical evaluation of all measurement results, wherein the measurement is carried out in at least two measurement series (M, N), the measurement results (M l . . . M m , N l . . . N n ) of each of the measurement series (M, N) being determined in mutually equidistant rotational positions of the specimen, each of the measurement series (M, N) comprising a specific number n, m of measurements, m and n being natural and mutually coprime numbers, the measurement results (M l . . . M m , N l . . . N o ) of each of the at least two measurement series (M, N) are evaluated independently of one another for non-rotationally symmetric wavefront errors (<W> m , <W> o ) on the specimen, the difference of the at least two non-rotationally symmetric wavefront errors (<W> m , <W> o ) being formed, whereupon the difference (<W m −<W> o ) that is formed is computationally rotated m or n times and the results are averaged out, and whereupon at least one of the wavefront errors (<W> m , <W> o ) is corrected with the result (<<W> m −W> o > m ) averaged in this way.