A CCD sensor is a "Charge Coupled Device", made up of a lot of microscopic pixels, which are sensitive to light.
The sensors are located in the focal plane. Two CCD sensors are dedicated to the asterosismology program, and two other CCD sensors to the exoplanet program.
The sensors dedicated to the asterosismology program :
- These are matrixes of 4 million pixels per CCD.
- Each pixel is a square of 13 microns.
- They work at an almost constant temperature, about –40°C, stabilized by an precise control system.
- The image of the stars is in the half of the detector called the "image area" (on the left side of the picture).
- The electrons stored in the image zone are then transferred to the memory zone to be counted.