microdensitometer


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microdensitometer

(mÿ-kroh-den-să-tom -ĕ-ter) An optical instrument that measures and records small changes in the transmission density on a photographic plate, such as the faint features in a spectrum. The plate, mounted on a carriage, is moved through a light beam. A photomultiplier measures the amount of light transmitted by the plate and the output is fed to a chart recorder or computer.

microdensitometer

[¦mī·krō‚den·sə′täm·əd·ər]
(spectroscopy)
A high-sensitivity densitometer used in spectroscopy to detect spectrum lines too faint on a negative to be seen by the human eye.
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The photographs taken on night 2 did not reveal anything unusual despite undergoing microdensitometer scans.
patent for "Spot Microdensitometer for the Spectral Density Analysis of Film." In addition, Shih was founder and director of the Center for Remote Sensing at the University of Florida.
The scattered intensities were obtained from the photographic films using a unidimensional microdensitometer. The scattered intensity (I) was obtained at different scattering angles ([Theta]) by averaging a number of diametrical readings through the center of the main beam position and subtracting the background from the intensity curve.
During the 1970s astronomers confirmed this characteristic pattern, now referred to as the "quadrupole azimuthal brightness asymmetry," by scanning scores of photographic plates of Saturn with a microdensitometer. It appears in the Voyager and Hubble Space Telescope images as well.
The scattered intensities were obtained from the photographic films using a one-dimensional microdensitometer. The scattered intensity (I) was obtained for different scattering angles ([Theta]) by averaging a number of diametrical readings through the center of the main beam position and subtracting the background from the intensity curve.
CCD cameras have replaced glass plates, image-processing software has supplanted scanning microdensitometers, and satellite-based star catalogs have eliminated the need to measure star positions six months before or after the eclipse.