photometry

2 ENTRIES FOUND:

pho·tom·e·try

noun \fō-ˈtä-mə-trē\

Definition of PHOTOMETRY

:  a branch of science that deals with measurement of the intensity of light; also :  the practice of using a photometer

Origin of PHOTOMETRY

New Latin photometria, from phot- + -metria -metry
First Known Use: 1824

pho·tom·e·try

noun \fō-ˈtäm-ə-trē\   (Medical Dictionary)
plural pho·tom·e·tries

Medical Definition of PHOTOMETRY

: a branch of science that deals with measurement of the intensity of light; also : the practice of using a photometer

photometry

noun    (Concise Encyclopedia)

Precision measurement of the brightness, colour, and spectrum of stars and other celestial objects to obtain data on their structure, temperature, and composition. About 130 BC Hipparchus used a system that divided the stars into six magnitudes, from brightest to faintest. Beginning in the 17th century, use of the telescope led to the discovery of many fainter stars, and the scale was extended. The use of photographic and, since the 1940s, photoelectric equipment has vastly extended the sensitivity and wavelength range of astronomical photometry. The main (UBVRI) classification system uses wave bands in the ultraviolet, blue, visual, red, and infrared ranges. More elaborate systems can distinguish giant and dwarf stars, detect metals in stars, and determine surface gravity.

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