Results 211 to 220 of about 601 (266)

Atmospheric refraction: a history

Applied Optics, 2005
We trace the history of atmospheric refraction from the ancient Greeks up to the time of Kepler. The concept that the atmosphere could refract light entered Western science in the second century B.C. Ptolemy, 300 years later, produced the first clearly defined atmospheric model, containing air of uniform density up to a sharp upper transition to the ...
Lehn, WH, van der Werf, S
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On Astronomical Atmospheric Refraction

Chinese Astronomy and Astrophysics, 2008
Abstract Through a comparison between the series expression and mapping function expression of the astronomical refraction, we believe that, as far as a specific atmospheric refraction model is concerned, the computational accuracy is not lower in the former than in the latter, and that the convergence is poorer in the theoretically derived series ...
Wei Mao, Lei Yang, Qiong-Xian Tie
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Computer-graphics analysis of atmospheric refraction

Applied Optics, 1978
Interactive computer graphics is applied to the transmission of visual images through the lower atmosphere. The required input data to the computer consist of an atmospheric temperature profile and light-pen sketches of three objects at various distances from the observer.
W H, Lehn, M B, E-Arini
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Interferometric atmospheric refractive-index environmental monitor

Applied Optics, 1995
Long, open-path, outdoor interferometric measurement of the index of refraction as a function of wavelength (spectral refractivity) requires a number of innovations. These include active compensation for vibration and turbulence. The use of electronic compensation produces an electronic signal that is ideal for extracting data.
J E, Ludman, J J, Ludman, H, Callahan, H J, Caulfield, D, Watt, J L, Sampson, J, Robinson, S, Davis, A, Hunt   +8 more
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A new atmospheric refractivity meter

International Journal of Electronics, 1987
The present paper describes a simple electronic system employing a hybrid technique for digital measurements of the atmospheric refractivity. The technique is based on processing the sensed analogue signals from temperature, humidity and pressure sensors in order to realize the following relation by hardware where N is the refractivity, h is the ...
SHAKER A. ABDULLA, KHALID M. IBRAHEM, ABDUL-KAREEM A. MOHAMMED, ASAAD M. JASSIM   +3 more
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Atmospheric Refraction and Lake Monsters

Science, 1979
A survey of reported sightings of lake monster phenomena suggests that many of them may be attributable to atmospheric image distortion. The existence of the necessary conditions (surface temperature inversion and hence strong atmospheric refraction) can be inferred from most of the reports.
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Solar position and atmospheric refraction

Solar Energy, 1990
Corrections are presented for computer program SUNAE. The SUNAE program, designed by Walraven, calculates the position of the sun in the sky. The authors present equations that overcome problems with the program in the estimation of sunrise and sunset hours.
H.D. Kambezidis, N.S. Papanikolaou
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Measurements of Atmospheric Refraction

American Journal of Physics, 1974
The variation of atmospheric refraction between the zenith distances 65° and 90° has been observed using a simple achromatic camera. A new formula gives the angle of refraction more accurately at large zenith distances than the familiar tangent ξ formula. The techniques used for camera calibration are also presented.
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Inversion of atmospheric refraction data

Journal of the Optical Society of America A, 1991
We present a general method of inverting numerical data describing the form of a mirage to yield the atmospheric refractive-index or temperature profile that caused the mirage. The method is applied to three analytically generated mirages and five experimentally observed mirages to demonstrate its effectiveness.
W. G. Rees, C. M. Roach, C. H. F. Glover
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Curious Atmospheric Refraction Effects

Nature, 1933
WHILE in a rowing-boat on the ocean during a sultry afternoon this summer I observed a very peculiar series of refraction phenomena that seem worth describing. A thunderstorm was brewing in the north-east far enough away so that the thunder was just audible. There was no sunshine. The wind had dropped and the sea was gently undulating.
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