PERFORMANCE OF THE ANGLE-OF-ARRIVAL CORRECTION SYSTEM OF THE I2T+ASSISTELLAR INTERFEROMETER

The Active Stabilization in Stellar Interferometry (ASSI) recombining table, developed at Office National d'Etudes et de Recherches Aerospat iales (ONERA), France, was implemented on the two-Telescope Interferom eter (I2T) of the Observatoire de la Cote d'Azur (OCA) in 1993, compen sating for the atmospheric turbulence wavefront fluctuations. Initial fringe observations were made in June 1994 with a 11 m North-South bas eline. In this paper, we report the performance of the ASSI table serv o system for correction of the angle of arrival. Tracking accuracy of about +/-0.24 arcsec was achieved in typical seeing conditions (r(o) g reater than or equal to 10 cm) and on m(v) = 2 sources. Collected data allows to compare theoretical with observed temporal power spectra of the angle of arrival fluctuations, using Kolmogorov model. Spatio-tem poral seeing parameters met during observations (Fried parameter r(o) and coherence time t(o)) are estimated.