Wavefront outer scale deduced from interferometric dispersed fringes

¹ Lab. Univ. d'Astrophysique de Nice (LUAN) UMR 6525 UNSA, Parc Valrose, 06108 Nice Cedex 2, France e-mail: maire@unice.fr
² OCA, GEMINI, UMR6203, Avenue Nicolas Copernic, 06130 Grasse, France
³ Astronomical Observatory, MSEP of Serbia 146007, Volgina 7, 11 050 Belgrade, Serbia and Montenegro

Received: 2 February 2005
Accepted: 4 November 2005

Abstract

In addition to site characterization, measurements of critical atmospheric parameters are required to design and to optimize future adaptive optic systems and long-baseline interferometers. It is possible to estimate seeing conditions by processing data obtained with existing High Angular Resolution instruments. We report the results of joint observations with the GI2T interferometer and the GSM site-testing monitor performed over a period of several nights. We compared estimates of the wavefront outer scale done at various baselines as well as the seeing (Fried's parameter). We processed interferometric data by calculating power spectra of dispersed fringe images. Deduced measurements of the optical path difference lead to the estimates of the outer scale. We found that the outer scale values obtained from the GI2T data are mostly in the 5-30 m range, in good agreement with GSM measurements.