This interactive page describes the different elements of the optical bench to test and calibrate the entire optics of the CHEOPS space telescope including the CCD detector. The photo was taken in the clean room of the Physics Institute of the University of Bern and the diagram shows the optical path of the installation.
To determine the spatial and wavelength response of the CCD it is necessary to illuminate it with a light source whose rays have to be parallel (like a star at infinity). The source must be uniform on the CCD surface to have the response of each pixel (flats fields) on one side, and punctual to determine the PSF on other side. An integrating sphere provides then a uniform illumination over the entire CCD surface and a highly stable source is used to simulate the response of the CCD to the illumination of a star. Moreover, both sources should be variable in wavelength.