The CoRoT optical design minimized stray light coming from the Earth and provided a field of view of 2.7° by 3.05°. The CoRoT optical path consisted of a diameter off-axis afocal telescope housed in a two-stage opaque baffle specifically designed to block sunlight reflected by the Earth and a camera consisting of a dioptric objective and a focal box. Inside the focal box was an array of four CCD detectors protected against radiation by aluminum shielding 10mm thick. The asteroseismology CCDs are defocused by 760μm toward the dioptric objective to avoid saturation of the brightest stars. A prism in front of the planet detection CCDs gives a small spectrum designed to disperse more strongly in the blue wavelengths.