Generalized-Scintillation Detection and Ranging (g-SCIDAR) has proven to be the most reliable and efficient technique for obtaining the vertical structure of the atmospheric turbulence through optical means. However, undesirable turbulence inside the telescope enclosure (dome and mirror seeing) is intermixed with the results. Processes for

Context: The first asteroseismology results from CoRoT are presented, on a star showing Sun-like oscillations. We have analyzed a 60 day lightcurve of high-quality photometric data collected by CoRoT on the F5 V star HD 49933. The data reveal a rich spectrum of overtones of low-degree p modes. Aims: Our aim was to extract robust estimates of the

The initial instrumentation of the 1.5 m solar telescope GREGOR on Tenerife will include a grating spectrograph with a spectro-polarimeter for the near infrared and a dual Fabry-Perot filter spectro-polarimeter for the "red" wavelength range from 530 to 860 nm. Both instruments are based on their predecessors that are presently operated at the

The structure and dynamics of small vertical photospheric magnetic flux concentrations has been often treated in the framework of an approximation based upon a low-order truncation of the Taylor expansions of all quantities in the horizontal direction, together with the assumption of instantaneous total pressure balance at the boundary to the non

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Using the T-matrix theory, we have performed an analytical study of the collective fast normal modes of an arbitrary system of loops. The obtained results allow to assess the dynamical effects of the interaction of loops and the frequency shifts with respect to the individual loops in an arcade as a function of the number of tubes. Furthermore, the