ESA Science & Technology - Testing the CHEOPS telescope

The pristine, integrated CHEOPS telescope is placed into a thermal vacuum chamber for optical performance tests and characterisation measurements at Leonardo-Finmeccanica.

The tests were carried out under vacuum and at temperatures ranging from -5 to -15 °C. The light source for the test was situated outside the chamber. Light passed through a window in the chamber's door and entered the telescope. The response of the telescope was measured by a temporarily-mounted CCD.

During these tests the position of the focal plane was determined so that the focal plane module can be positioned correctly in the next phase of integration.