Pyrgeometer MS-202 is designed to measure long-wave radiation above 3µm. A coated Silicon dome transmits incident radiation which above 3µm by cutting off the shorter wavelengths of the Sun spectrum. A electronic compensation circuit with a thermistor is integrated in the MS-202. This circuit is used for the sensor body temperature measurement or to measure Long wave downward radiation in the active mode. The analog output voltage of the detector is linear to the net radiation emitted by the atmosphere and ground. A thermistor dome temperature sensor is available as an option. Pt-100 temperature sensor for both the sensor body temperature and the dome temperature is also available as an option.