A search for very low-mass and brown dwarfs using Virtual Observatory Tools for cross-correlation of large area catalogs and databases (DENIS, IPHAS, SDSS, 2MASS) is presented. We have obtained follow-up imaging and spectroscopy for some of the candidates. First results from spectroscopic follow-up of candidates will be reported.

We study long-term evolution of stellar bars in disk galaxies embedded in live dark matter halos. Using numerical modeling with N = 1.2 × 106 particles, we find that this evolution proceeds through recurrent dynamical instabilities and associated secular changes. We have studied the vertical buckling instability in the bar and find that it shortens

The quality of astronomical observations is strongly related to the quality properties of the atmosphere. This parameter is important for the determination of the observation modes, and for observation program, the socalled flexible scheduling. We propose to present the implementation of the WRF model in order to routinely and automatically

We present seeing measurements from Mt. Holomon (Chalkidiki, Greece), a possible site for the establishment of a new University of Thessaloniki Observatory, using the Hartman - DIMM method. After two years of systematic observations we present the first robust results and give a first evaluation of the astronomical seeing characteristics, which are

Rotation is thought to drive cyclic magnetic activity in the Sun and Sun-like stars. Stellar dynamos, however, are poorly understood owing to the scarcity of observations of rotation and magnetic fields in stars. Here, inferences are drawn on the internal rotation of a distant Sun-like star by studying its global modes of oscillation. We report

Several options for the GTC (Gran Telescopio Canarias) installations have been evaluated. In particular, different dome types and distribution schemes for the support areas to be incorporated in the installation have been assessed. In order to select the dome type, a technical-economic study has been carried out, in which the most important