The Advanced Technology Solar Telescope (ATST) will be the world's largest aperture solar telescope, and is being designed for high resolution, IR, and coronal research. It must be located at a site that maximizes the scientific return of this substantial investment. We present the instrumentation, analysis and results of the ATST site survey. Two

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Vertical instabilities, buckling, in stellar bars weaken and shorten the bar. This can interrupt the bar-induced gas inflow into the central kpc of a galaxy for ˜ 1 Gyr. The subsequent bar growth in length and in amplitude can lead to a recurrent buckling. The first buckling results in the formation of a peanut/boxy-shaped bulge when viewed edge-on

Photometric and spectroscopic parameters for sigma Ori very low-mass stars and brown dwarfs candidates. (1 data file).

The activities related to the preparation of the asteroseismic, photometric space mission COROT are described. Photoelectric observations, wide-field CCD photometry, uvbyβ calibrations, and further time series have been obtained at different observatories and telescopes. They have been planned to complete the COROT program in the direction of the

A new method for absolute polarimetric calibration of large telescopes is presented. The proposed method is highly accurate and is based on the calibration of a small subaperture, which is then extended to the full system by means of actual observations of an astronomical source. The calibration procedure is described in detail along with numerical