(Last edited: Sunday, 1 October 2023, 7:00 PM)


Short Definition:

A photometer is an instrument used to measure the strength of electromagnetic radiation. It is the primary tool used in the field of photometry, a field that focuses on the study of the emitted intensity of the electromagnetic radiation of an astronomical body.

Detailed Definition:

One of the devices used in the research electromagnetic radiation is the photometer. The most crucial component of the photometer is a photoresistor, photodiode, or photomultiplier, varying on the type of the photometer, which is responsible for the conversion of light into electric current. Among others, photometers most commonly measure illuminance, irradiance, light absorption, fluorescence, and luminescence. Most of the photometers measure light by the incoming flux, however, photon counting is also a viable technique. Light detection occurs after the light passes through a filter, which then distinguishes the respective wavelengths. Photometers are used in many medical, laboratory and industrial applications. Uses include the identification and quantification of chemical components, pharmaceutical quality control and astronomical calculations.


"photo-" - Greek, combining form of phōs (genitive phōtos) - word-forming element meaning "light"

"-meter" - French -mètre, Greek metron - word-forming element meaning "a measure"

Sample Sentence(s):

"Photometers are used to gather data for improved lunar calibration of Earth-observing instruments."

"A photometer is often used in conjunction with a telescope."

Translations of Terms/Concepts into Partner Languages

French: Photomètre

German: Fotometer

Polish: Fotometr

Swedish: Fotometer

Links to Videos/Articles:

» Dictionary of Space Concepts