Target Sun & Earth Here we see the distortions within largest CCD cell that will fit into a Paraboloid's coma free image area when using a 9 point floatation cell  In this case the coma free radius of the paraboloid is very close to the full image disk of the mirror.  Use a True Parabolic Mirror in its place, and the coma free image area includes the whole image disk.  The black areas are unused CCD pixels that act as place holders when collecting the frames that make up the final image. Replace the "Thin" True Parabolic Mirror with a "Thick" True Parabolic Mirror, and you loose both the coma and the support induced distortions, - as I do with my AcuBright Telescopes. Here we see the distortions within largest CCD cell that will fit into a Paraboloid's coma free image area when using a 27 point floatation cell  Using a True Parabolic Mirror in its place, again makes the coma free image area include the whole image disk.  Replace the "Thin" True Parabolic Mirror with a "Thick" True Parabolic Mirror, and you eliminate both the coma and the induced distortions.