<p>A method for centering a circular optical element using a non self-centering chuck adapted to grip the element at two strengths. The element is rotated in the chuck while measuring the lateral position of its outer rim with a probe. The positions of maximum and minimum run-out of the element as a function of its angular position are determined. Chuck rotation is stopped at an angular position with the maximum rim run-out positioned at a predetermined point. The chuck grip is reduced such that the element is still held in the chuck but can be moved in a lateral direction without damaging its surface. The element is moved in a direction connecting the predetermined point of maximum run-out and the axis of rotation of the chuck, in order to reduce the run-out of the element. The procedure is repeated until the desired centering is achieved.</p>
