As mentioned several times in other parts of our website, measurement of cloud cover is a major topic for ATMOS. Instruments that we propose are based on a passive technology analyzing thermal infrared radiations emitted by clouds proportionally to their structure and altitude. As you could see going forward in this section of our website, the range includes two types of instruments some of them are based on a scanning technology of the sky dome (rotating turret) and on measurement of time series ( four fixed sensors oriented along the main cardinal directions).