请输入您要查询的字词:

 

单词 photometry
释义
photometry

Physics
  • The study of visual radiation, especially the calculations and measurements of luminous intensity, luminous flux, etc. In some cases photometric calculations and measurements extend into the near infrared and the near ultraviolet.

    In photometry, two types of measurement are used: those that measure luminous quantities rely on the use of the human eye (for example, to compare the illuminance of two surfaces); those called radiant quantities rely on the use of photoelectric devices to measure electromagnetic energy. See also photometer.

    http://www.kayelaby.npl.co.uk/general_physics/2_5/2_5_3.html Photometric data available at the NPL website


Astronomy
  • The science of the measurement of light. The earliest estimates of star brightnesses were made with the naked eye, which formed a basis for the magnitude scale used in astronomy. Now, professional astronomers use photometers to compare objects under study with standard stars. Broad-band filters are used for the faintest objects to achieve sufficient signal, while brighter stars can be measured with intermediate-band or narrow-band filters. The filters are carefully chosen to reveal characteristics of the spectrum such as absorption lines in stars and galaxies, and emission lines and bands in nebulae. Magnitudes from different filters are usually compared to obtain a colour index. Satellites have extended astronomical photometry into the ultraviolet and infrared. See also broad-band photometry; BV photometry; DDO photometry; Geneva photometry; high-speed photometry; infrared photometry; intermediate-band photometry; Johnson photometry; Kron–Cousins RI photometry; narrow-band photometry; RGU photometry; SDSS photometry; six-colour system; UKIDSS photometry; ultraviolet photometry; VILGEN photometry; Vilnius photometry; Walraven photometry.


Geology and Earth Sciences
  • A general term for the physical measurement of the ultraviolet, visible, and infrared portions of the electromagnetic spectrum.


随便看

 

科学参考收录了60776条科技类词条,基本涵盖了常见科技类参考文献及英语词汇的翻译,是科学学习和研究的有利工具。

 

Copyright © 2000-2023 Sciref.net All Rights Reserved
京ICP备2021023879号 更新时间:2024/6/30 23:48:28