CHP1 Pyrheliometer for Direct Solar Irradiance Measurement

The CHP1 pyrheliometer is a solar irradiance sensor (radiometer) that measures the direct beam radiation of the sun (Direct Normal Irradiance, DNI). The CHP1 pyrheliometer is the most commonly used radiometer for the measurement of direct normal irradiance (DNI) and offers high accuracy and reliability. As the CHP1 Pyrheliometer only measures a narrow beam of the sun’s irradiance it is necessary for it to always be accurately pointing at the sun. In order to achieve this a sun tracker device such as the SOLYS2 is required.


CHP1 Pyrheliometer by Kipp and Zonen

The CHP1 pyrheliometer fully complies with the most current ISO and WMO performance criteria for First Class Normal Incidence Pyrheliometer. Every CHP1 is calibrated upon manufacture and is supplied standard with a WRR traceable calibration certificate.


Spectral range (50% points) 200 to 4000 nm
Sensitivity 7 to 14 µV/W/m²
Response time < 5 s
Zero offset B < 1 W/m²
Temperature dependence of sensitivity (-20 ºC to +50 ºC) < 0.5 %
Field of view 5 ±0.2 °
Operational temperature range -40 to +80 °C
Non-linearity < 0.2 %
Maximum solar irradiance 4000 W/m²
International standards (ISO) First Class

The CHP1 pyrheliometer has a narrow-angle of view. As such, it needs to be mounted on a sun-tracking device to ensure it always accurately points directly at the sun. Read more on the CHP1 Pyrheliometer here.

The CHP1 pyrheliometer has a quartz window to cover the total solar spectrum of solar radiation between 200 to 4000 nm. Fitted with a high-quality connector installation and maintenance are fast and simple. To protect the components from moisture the CHP1 is fitted with a screw-in drying cartridge which can be easily removed for fast changeover of the drying desiccant.

As standard CHP1 comes fitted with: 1 x 10 kΩ thermistor and 1 x  Pt-100 temperature sensor. Therefore small temperature dependency of sensitivity can be corrected in post-processing using the supplied data.


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