OPTICAL TESTING
Shack-Hartmann vs. Hartmann Test
In the classical Hartmann test, a screen with holes is placed before the element being tested. The spots corresponding to these holes are recorded on a CCD, before or after the focus. The positions of these spots are mapped back onto the optical element, and the difference between the positions of these spots and the holes of the screen are used to compute the aberrations. This method is mostly obsolete now, as the Shack-Hartmann test has replaced it.
