Testing the optics of Large Millimeter Telescope (LMT)

The main ideas to test the optics of the LMT, based on the use of null screens are revised. The design method of an array of light sources located in such a way that, by reflection on the test surface, the images of these sources are aligned in a regular grid (square of radial) is qualitatively described. Some experimental results obtained with small surfaces are presented and some modifications to be implemented in order to improve the method will be discussed.