METHOD FOR THE OPTICAL CHARACTERISATION OF LARGE MIRRORS CONSISTING IN RECORDING THE LIGHT REFLECTED FROM A STAR

摘要

The invention relates to a method for the optical characterisation of large mirrors consisting in recording the light reflected from a star. The light reflected from a star in the mirror is recorded with a CCD camera and used to determine the components of the vector normal to the mirror at numerous points. For this purpose, the camera, which is positioned facing the mirror in the focal region or the concentration region thereof, takes images of the mirror and records the bright zones caused by the reflection of the light from the star. The invention also relates to various methods which can be used easily to obtain a large number of images and, as a result, a more precise characterisation. The inventive method can be used to obtain the complete optical characterisation of any mirror having a focal length and size much greater than the diaphragm of the camera. More specifically, for solar concentrators, said method can be used to measure the light intensity distribution in the concentration region, to determine offset errors and to monitor alignment quality in facet mirrors.