Effects of Atmospheric Turbulence on Optical Instrumentation

Effects of Atmospheric Turbulence on Optical Instrumentation
Author: Randolph A. Becker
Publisher:
Total Pages: 17
Release: 1961
Genre:
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The results of research on optical turbulence at White Sands Missile Range are presented. It has been shown that elevating camera stations 33 feet above ground level can yield nearly a threefold increase in optical resolution during periods of atmospheric turbulence. Early research postulated the existence of thermal-induced air-lenses as the cause of optical turbulence effects. Recent research has shown that air-lenses can account for most of the observed effects. The 'prism' concept of turbulence appears to be unnecessary for explaining trubulence -induced image motion. The dependence of the optical effects of turbulence upon exposure time and aperture size is discussed qualitatively. The source of optical turbulence in the atmosphere and a method of measuring the trubulence-generating potential of various terrain surfaces are described on the basis of micrometerology. This research has been limited to an investigation of optical turbulence during the period from sunrise to sunset. However, many of the results apply to the nighttime turbulence encountered by astronomers. (Author).

Optical Turbulence Forecasting

Optical Turbulence Forecasting
Author: Edmond M. Dewan
Publisher:
Total Pages: 76
Release: 1980
Genre: Atmospheric turbulence
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This report is a tutorial on the effects of atmospheric turbulence upon systems which rely upon the propagation of LASER beams. In addition to providing a simplified presentation of turbulence theory and optical effects, it describes the state of the art of the new technique of radiosonde estimation of index of refraction fluctuations. Suggestions are given for future research which will help to answer current Air Force needs. The feasibility of some laser systems will depend upon the value of r0, the coherence length (which is related to “C2n” which in turn is related to the degree of turbulence). At present, the statistics of “r0” are inadequate.

An Investigation of Atmospheric Turbulence by Stellar Observations

An Investigation of Atmospheric Turbulence by Stellar Observations
Author: Jack Lytle Bufton
Publisher:
Total Pages: 188
Release: 1971
Genre: Astrophysics
ISBN:
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This study of the optical effects of atmospheric turbulence concentrates on the stellar observation problem. When an infinite plane wave from an incoherent stellar source is sampled by an earth-based telescope, the resultant stellar image exhibits random fluctuations in intensity, position, and size due to turbulence-induced scattering in the intervening atmosphere. One familiar aspect of this problem is the scintillation of starlight apparent to the naked eye. The central aim is to express optical statistics in terms of refractive-index structure constant which pertains to strength of turbulence along the optical path. Data is presented on stellar and meteorological observations made between fall 1968 and spring 1969 with a 0.152-meter diameter refracting telescope. Data was recorded simultaneously on the three parameters of image intensity, motion, and size. The data is interpreted in terms of the theory and used to estimate strength of turbulence. The central result is a series of profiles for refractive-index structure constant along the vertical path. These are constructed using stellar data to calculate parameters of a model.