Solarimeter is a weather instrument used widely for measuring the flux of solar radiation through a surface. The accurate weather forecast can be obtained only with the help of various weather instruments. A person responsible for the weather forecast is known as meteorologist. Meteorologists with the help of these instruments collect various data’s before predicting the weather.

For the past few decades the entire weather forecast system had been improved constantly to get a better, accurate and faster result. A weather forecast helps one to plan their activities for the week ahead. Solarimeter is considered to be one of the most popular and useful instrument used for weather forecasting.

The intensity of the entire global solar radiation on the surface of the earth in both direct and defused sunlight is measured by Solarimeter. This type of measuring device is known as ‘pyranometer’. The solar radiation derived from the absorption of heat by a black body is developed into energy that is measured by the Solarimeter.

Solarimeter is a passive device that does not require any power supply. The voltage output provided by the Solarimeter is read by a datalogger or other related reading device. The reading is then converted into watts per square meter (W/m2) to get the final result.

The Solarimeter was developed by Father Angelo Bellani, an Italian priest. He was the inventor of the ‘actinometric’ method. The Solarimeter has a weatherproof body with an aluminium coat. The sensor based upon a silicon photo detector is placed within this body. This body condition is suitable for long term outdoor operation.