It is an instrument for measuring radiation values, especially that of solar rays. It is a word formed by the Greek voices 945; 954; 964; 953; 957; 959; 962; ( actinus "lightning" ) 956; 949; 964; 961; 959; 957; ( metron "measure" ) .
It is the name of a device that serves to measure the intensity of solar radiation. Apparatus that measures the intensity of the sun's rays. It is also often called a pyranometer or solarimeter.