Top row: 2D map of M1 and M2 obtained with a ZYGO interferometer (12 mm diameter). Middle row: residual errors (specification map subtracted from measurement map) for M1 and M2 over the pupil area (7.7 mm). Bottom row: corresponding measured 1D azimuthally averaged radial profile (blue line) compared to specification (black line) for M1 (left) and M2 (right). The interferometer resolution is 16 m per pixel.
