First single star scidar measurements at Dome C, Antarctica

Abstract

Aims. First operational running of the Single Star Scidar (SSS) under harsh weather conditions at Dome C in Antarctica. Continuous monitoring of the optical turbulence and wind speed profiles throughout the whole atmosphere. Methods. SSS is mainly composed of “off the shelf” light-weight components, a 16 inches telescope installed on an equatorial mount. Scintillation patterns are computed (auto and cross-corre lations) in real time and analyzed off line to retrieve continuously vertical profiles of optical turbulence C 2 (h) and wind speed V(h), from ground up to 20 km . Results. Using a simulated annealing method, we have analyzed about 6.5 hours of observations, putting into evidence the strong s urface layer contribution to seeing degradation. SSS results show a good agreement with simultaneous measurements with a Differential Image Motion Monitor as well as weather archive from NOAA. Conclusions. SSS has shown its usefullness for site characterization sin ce it measures simultaneously C 2 N and V profiles, from which most of adaptative optic parameters are deduced, such as isoplanatic angle and coherence time of the wavefront. Due to its small size, it is well adapted to site characterization, even when low infrastructure is available.