Azimuthal position error correction algorithm for absolute test of large optical surfaces

Abstract

Absolute test needs test part rotation to separate errors of the interferometer itself from errors due to the test surfaces. At this time, previous absolute test algorithms assume no azimuthal position error during part rotation. For large optics whose diameters are 0.6 m and over, however, exact rotations are physically difficult. Motivated by this, we propose a new algorithm that adopts least squares technique to determine the true azimuthal positions of part rotation and consequently eliminates testing errors caused by rotation inaccuracy. (c) 2006 Optical Society of America.