<title>Atmospheric phase fluctuation measurement: interferometric results from the WHT and COAST telescopes</title>

Abstract

We have used interferometric methods to track the atmospheric phase fluctuations at two astronomical sites: the Observatorio del Roque de los Muchachos in the Canary Islands, the site of the 4.2-m William Herschel Telescope (WHT), and the Lord's Bridge observatory in Cambridge, the location of the Cambridge Optical Aperture Synthesis Telescope (COAST). At both sites the atmospheric perturbations are well characterized by Kolmogorov turbulence. At the WHT we find no obvious evidence for saturation of the turbulence over the range of spatial scales investigated, although there are rapid variations in the seeing on timescales of minutes.