The Effects of Atmospheric Turbulence on Astronomical Observations

Turbulence in the Earth’s atmosphere is a major obstacle to the detection of planets with coronographic and interferometric methods from the ground. It limits the contrast achievable with high-resolution imaging and the precision of astrometric measurements. Atmospheric turbulence also determines many of the key design parameters of adaptive optics systems and interferometers: site selection, operating wavelength, aperture size, temporal bandwidth of the servo loops, and integration times. It is therefore important to understand how turbulence is generated in the atmosphere, and how its effects on the propagation of light can be quantified. This chapter gives a brief outline of atmospheric turbulence in the “standard” Kolmogorov model; more detailed treatments of this topic have been given by Roddier (1981 and 1989), Fried (1994), and Hardy (1998).