Astrophysics (Index)About

photometer

(instrument measuring brightness)

A photometer is a general term for an instrument measuring brightness. The term is commonly used in astronomy for an astronomical instrument specifically designed to measure the brightness of a single star, a usage that predates the advent of CCDs. A typical design incorporates a photomultiplier tube, and can be thought of as a single pixel large enough to capture all the light of an airy disk. The terms photo-electric photometer and photo-electric photometry were common in the early/middle 20th century to distinguish their use from astronomical photography.

In recent astronomy, CCDs (and other such sensor arrays) are literally grids of tiny photometers, the grid laid out so an image can be focused on it: the apparent brightness of a star can be found by adding the count of all the photons detected in the Airy disk of the star in question.


(EMR,visible light,instrument type)
Further reading:
https://en.wikipedia.org/wiki/Photometer
https://en.wikipedia.org/wiki/Photometry_(astronomy)
https://ui.adsabs.harvard.edu/abs/1980IAPPP...3....7W/abstract

Referenced by pages:
2dF Galaxy Redshift Survey (2dFGRS)
ARGOS
Gaia
High Altitude Observatory (HAO)
Hubble Space Telescope (HST)
IRTS
Large Altazimuth Telescope (BTA-6)
Mercator Telescope
SPHEREx
Spitzer Space Telescope (SST)
STELLA
Telescopio Nazionale Galileo (TNG)
ZEPLIN

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