The CM121 Shadow Ring is designed to be used with any Kipp & Zonen pyranometers, smart pyranometers, pyrgeometers or UV Radiometers to shield the sensor from direct radiation. The combination of one of these sensors and the CM121 offers a simple solution to the problem of measuring diffuse radiation from the sky. Naturally, the ring will also intercept some of the diffuse radiation from the sky. The ring has a width/diameter ratio of 0.185 and ...