ARISTIDI , E.

We present long term site testing statistics obtained at Dome C, Antarctica with various experiments deployed within the Astroconcordia programme since 2003. We give values of integrated turbulence parameters in the visible at ground level and above the surface layer, vertical profiles of the structure constant C_n^2 and a statistics of the...

This paper gives an introduction to the theory of orthogonal projection of functions or signals. Several kinds of decomposition are explored: Fourier, Fourier-Legendre, Fourier-Bessel series for 1D signals, and Spherical Harmonic series for 2D signals. We show how physical conditions and/or geometry can guide the choice of the base of functions...

This paper presents numerical illustrations of the effects of clipping of photoevents in speckle interferometry and speckle masking. The clipping is due to a saturation of the photon-counting detectors that cannot count more than one photon per pixel, causing the image to be composed of "0" and "1". The theoretical basis for this study has been...

This paper presents some statistical information about the Concordia turbulent surface inversion layer, regarding height and turbulent energy, its contribution to the peculiar local seeing, and the free atmosphere seeing encountered just above this surface layer.

On the Antarctica plateau, a joint project of french and italian polar programmes in just near completion: the Concordia station will be open for winterover operation in 2005. The high altitude and high latitude of this site, the exceptionally cold, clear and stable atmosphere, the almost indefinitely flat snow surface and the not so difficult...

This paper describes a method of beam-combination in the so-called hypertelescope imaging technique recently introduced by Labeyrie in optical interferometry. The method we propose is an alternative to the Michelson pupil reconfiguration that suffers from the loss of the classical object-image convolution relation. From elementary theory of...

International audience

We present in this paper a technique for imaging binary stars from speckle data. This technique is based upon the computation of the cross-correlation between the speckle frames and their square. This may be considered as a simple, easy to implement, complementary computation to the autocorrelation function of Labeyrie's technique for a rapid...