It turns out that the deformation is almost exactly spherical. One very simple solution is to polish the disk to a convex spherical figure which precompensates the distortion. The problem with this approach is that the deflection will be exactly compensated at only one rotation speed. A simpler solution is to fabricate the disk from beryllium. The simplest solution is to ignore the problem - which has been done temporarily to acquire the data shown herein. The consequence may be a moderate reduction of modulation efficiency at higher speeds. At the highest scan rate of 667 scans per second (333 rps) for the data shown here, the distortion should be slightly less than half the value predicted here for 1000 scans per second.