TURBULENCE PROFILES WITH GENERALIZED SCIDAR AT SAN-PEDRO-MARTIR-OBSERVATORY AND ISOPLANATISM STUDIES

The results obtained from 3398 vertical profiles of atmospheric turbul ence measured during I I nights at the Observatorio Astronomico Nacion al in San Pedro Martir (Baja California, Mexico) are presented. The ob servations were carried out with the generalized scidar (GS) installed at the 1.5 m and the 2.1 m telescopes of that site, in 1997 March and April. The open-air seeing was measured with a differential image mot ion monitor (DIMM). The GS can detect turbulence profiles along the wh ole optical path, unlike the classical scidar; which is insensitive to low-altitude turbulence. For the first time, to our knowledge, profil es including turbulence near the ground are monitored and statisticall y analyzed. Isoplanatic angles for speckle interferometry and adaptive optics (AO) in either full or partial compensation are deduced, as we ll as the focus anisoplanatism parameter for sodium laser guide stars. The advantage of minimizing the distance between the turbulent layers and the conjugated plane of the deformable mirror of an AO system is studied. The comparison of GS profiles obtained at both telescopes, to gether with DIMM measurements, show that the turbulence near the groun d is more strongly dominant at the 1.5 m telescope than at the 2.1 m t elescope, where the median values of the seeing near the ground, in th e free atmosphere and in the whole optical path are 0.'' 56. 0.'' 44 a nd 0.'' 77. respectively, These values are comparable to or better tha n those of the major astronomical observatories, although a larger dat a sample is needed for a definitive comparison.