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Light propagation through the atmosphere and the properties of images formed by large ground-based telescopes

1991; Optica Publishing Group; Volume: 8; Issue: 2 Linguagem: Inglês

10.1364/josaa.8.000346

1520-8532

T. Stewart McKechnie,

Optical Systems and Laser Technology

A fresh look is taken at how light propagates through the atmosphere and how atmospheric turbulence affects images formed by large ground-based telescopes. Telescopes with fixed and adaptive optics are considered. The approach is based on a layered model of the atmosphere. It is shown that the atmosphere can be represented by an equivalent phase screen for the two quantities that determine most of the important image properties—the atmospheric modulation transfer function and the spectral correlation function. Techniques are described for measuring the parameters that define the equivalent phase screen. Expressions are given in terms of screen parameters for a number of image properties. Many of these properties are different from those in the conventional literature. Diffraction-limited cores in star images are discussed. An optimum wavelength at which resolution is maximized is also discussed. Resolution of the order of 0.05 arcsec is possible at this wavelength, but only if the telescope is near diffraction limited. The optimum wavelength can be used to produce maximum energy density at the focus of a ground-based laser beam directed at a target in space.