Light from a point source near the center of curvature is reflected from the mirror, over which a screen pierced with hundreds of holes is placed. The light then reconverges near the source where it is intercepted by a photographic plate positioned just inside or outside the focus. The image records aberrations and can be analyzed to yield the mirrors figure.
Foucault Test, Mirror Tests, Rayleigh Water Test, Ronchi Test, Terebizh Null Test
