Sensitivity 0.12 mV per W mˉ² (variable from sensor to sensor, typical value listed) Calibration Factor (Reciprocal of Sensitivity) 8.5 W mˉ² per mV (variable from sensor to sensor, typical value listed) Calibration Uncertainty ± 5 % Measurement Range -200 to 200 W mˉ² (net longwave irradiance) Measurement Repeatability Less than 1 % Long-term Drift Less than 2 % change in sensitivity per year Non-linearity Less than 1 % Detector Response Time Less than 0.5 seconds Field of View 150 ˚ Spectral Range 5 to 30 µm Temperature Response Less than 5 % from -15 to 45 C Window Heating Offset Less than 10 W mˉ² Zero Offset B Less than 5 W mˉ² Tilt Error Less than 0.5 % Uncertainty in Daily Total ± 5 % Temperature Sensor 30 kΩ thermistor, ± 1 C tolerance at 25 C Output from Thermistor 0 to 2500 mV (typical, other voltages can be used) Input Voltage Requirement for Thermistor 2500 mV excitation (typical, other voltages can be used) Heater 780 Ω, 15.4 mA current draw and 185 mW power requirement at 12 V DC Dimensions 27.5 mm height, 23.5 mm diameter Mass 100 g Warranty 4 years against defects in materials and workmanship Manufactured Assembled in the USA