G-Scidar measurements of the optical turbulence with standard and high vertical resolution at Mt. Graham

Since November 2004 we measured the optical turbulence (C2N profiles) with a Generalized Scidar (GS) placed at the focus of the Vatican Advanced Technology Telescope at Mt.Graham, Arizona. The present statistic consists in measurements related to 43 nights covering different periods of the solar year. In this paper we calculate the statistics of the astroclimatic parameters (C2N, seeing É› , isoplanatic angle theta0, wavefront coherence time tau0) and we compare these values with those measured above other top level astronomic sites. All profiles are reduced into a form suitable to be used as inputs for adaptive optics point spread function simulations for the conceptual design of the Laser Guide Star Facility supported by a GLAO system of the Large Binocular Telescope. With GS measurements done observing wide binaries (30-35 arcsec), the turbulence in the first kilometer above the ground is characterized with the vertical resolution (200-250 m) required for the optimization of a 4 arcmin field of view AO system. It is the first time that are published measurements of the optical turbulence vertical distribution above a mid-latitude site with such a high vertical resolution and such a high statistical reliability. On 8 of those nights, employing cross-correlation scintillation maps of wide binaries and the method described in Ref.[1] we characterize the distribution of the optical turbulence in the first kilometer at the extremely high vertical resolution of 20-30 meters