First single star scidar measurements at Dome C, Antarctica

Laboratoire H. Fizeau, UMR6525, Université de Nice, Observatoire de la Côte d'Azur, Parc Valrose, 06108 Nice - France e-mail: vernin@unice.fr

Received: 9 October 2008
Accepted: 30 January 2009

Abstract

Aims. We investigate the first operational running of the Single Star Scidar (SSS instrument) under harsh weather conditions at Dome C in Antarctica and examine continuous monitoring of the optical turbulence and wind speed profiles throughout the atmosphere.

Methods. SSS is mainly composed of commercially available light-weight components and a 16 inch telescope installed on an equatorial mount. Scintillation patterns were computed (auto and cross-correlations) in real time and analyzed off line to retrieve continuously vertical profiles of optical turbulence and wind speed V(h), from the ground up to 20 km.

Results. Using a simulated annealing method, we have analyzed about 6.5 h of observations, revealing the strong surface layer contribution to seeing degradation. SSS results show a good seeing agreement with simultaneous measurements with a Differential Image Motion Monitor, even under very good seeing as low as 0.2 arcsec, as well as wind speed agreement when compared to the weather archive from NOAA.

Conclusions. SSS has shown its usefulness for site characterization since it simultaneously measures and V profiles, from which most adaptative optic parameters are deduced, such as isoplanatic angle and coherence time of the wavefront. Due to its small size, it is well adapted for site characterization, even when low infrastructure is available.