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Apogee Instruments' themopile pyrgeometers are accurate, stable, durable, and cost effective.

Apogee Instruments Upward-looking Pyranometer   Apogee Instruments Downward-looking Pyrgeometer




Unique Design
Designed to optimize performance and price. The filter, blackbody thermopile detector, and thermistor (to measure detector temperature) are all contained in a compact housing that provides improved thermal coupling.


Accurate, Stable Measurements
Calibration in controlled laboratory conditions is traceable to the World Infrared Standard Group in Davos, Switzerland. Long-term non-stability determined from multiple replicate pyrgeometers in accelerated aging tests and field conditions is less than 2 % per year.


Rugged, Self-cleaning Housing
The patented domed shaped sensor head for the upward-looking model facilitates runoff of dew and rain to keep sensor clean and minimize errors caused by dust blocking the radiation path. Sensors are housed in a rugged anodized aluminum body and electronics are fully potted.

On-board Heater
A 0.2 W heater keeps water (liquid and frozen) off the sensor and minimizes errors caused by dew, frost, rain, and snow blocking the radiation path.

Typical Applications
Applications include longwave radiation measurement in agricultural, ecological, and hydrological weather networks and renewable energy applications.


A thermally-insulated base is included to be mounted between the sensor and leveling plate. The AL-120 Solar Mounting Bracket with Leveling Plate facilitates mounting the sensor to a mast or pipe. The AL-100 Solar Sensor Leveling Plate is designed to level the sensor while sitting on a flat surface or mounting to a surface.

Warranty and Support
All Apogee products are backed by an industry-leading four year warranty and outstanding customer support.



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  Technical Information
Technical Information
Find knowledge base articles, manuals, FAQs, technical support, and more.
+ Can I add additional cable to my sensor?
Yes, if properly spliced, the signal from the sensor is not affected by splicing on additional cable. We have tested splicing up to 100 meters of cable. For information on how to create a proper waterproof splice, please visit our instructional webpage or watch our video.

We offer custom cable lengths of our high quality cable and splice kits that can be ordered at the time of purchase or at a later date.


spec sheets
Specification Sheets




How to Use the AL-120 Leveling System