Electromagnetic radiation meters

thumb|A photometer A photometer is an instrument for measuring photometric quantities such as luminous flux, illuminance, or luminance.

thumb|210px|An example of a Crookes radiometer. The vanes rotate when exposed to light, with faster rotation for more intense light, providing a quantitative measurement of electromagnetic radiation intensity. A radiometer is an instrument for measuring radiometric quantities such as radiant flux (power), irradiance, or radiance. Definitions typically limit radiometry to optical radiation, but some definitions include other kinds of electromagnetic radiation. Radiometers typically measure infrared radiation, visible radiation (light), ultraviolet radiation, or some combination of these.

light meter used in photography

device that rotates under influence of light

thumb|280px|Fluorometer designed to measure chlorophyll fluorescence in plants

radiometer that measures energy in the one millimetre to meter wavelengths

instrument for measuring the net radiation on Earth's surface

measurement device used in telecommunications

thumb|right|450px|Example of a pyrgeometer

thumb|upright=1.0|right|ECOSTRESS radiometer

A spectroradiometer is a light measurement tool that is able to measure both the wavelength and amplitude of the light emitted from a light source. Spectrometers discriminate the wavelength based on the position the light hits at the detector array allowing the full spectrum to be obtained with a single acquisition. Most spectrometers have a base measurement of counts which is the un-calibrated reading and is thus impacted by the sensitivity of the detector to each wavelength. By applying a calibration, the spectrometer is then able to provide measurements of spectral irradiance, spectral radi