Proceedings Article | 25 August 2005
KEYWORDS: Charge-coupled devices, Cameras, Electronics, Stars, Interfaces, Calibration, Telescopes, Planets, Point spread functions, Quantum efficiency
The Corot project, developed in the framework of the CNES small satellite program with a wide European cooperation, will be launched in 2006. It is dedicated to seismology and detection of telluric planets. It will perform relative photometry in visible light, during very long (150 days) observing runs in the same direction. Both programs are running simultaneously and about 50.000 stars will be observed during the 3 years life. The concept of the instrument is based on an off-axis telescope (27 cm pupil, 3° square field of view), a dioptric objective images the stars on a focal plane. The focal plane is made of 4 CCDs, 2k*4k pixels, AIMO and frame transfer, at -40°C, two for each scientific programs. Electronics boxes manage the CCD readout, the thermal control and house-keeping, onboard software makes pre-processing and data reduction. As the expected signal is made of very small fluctuations expressed in ppm (part per million) a specific calibration of all the photometric chain and sub-systems is necessary. We have developed a specific test bench to calibrate CCDs. The manufacturer (E2V) provided us 10 CCDs and we realized calibration tests on them to be able to choose 4 CCDs for the flight focal plane (with different optimizations for the two scientific programs). Thereafter the camera sub-system has been integrated and calibrated on a specific test bench. This sub-system is made of a dioptric objective, focal plane, electronics boxes, mechanical and thermal equipment. We will present the camera sub-system (constraints and design), the test bench, and the results of the different tests : CCD calibration, radiation effects, Focal-Plane integration, optical setup, thermal balance and Camera calibration.
