The GTC (Gran Telescopio Canarias) is a 10,4 meter segmented telescope currently being integrated at the ORM in La Palma, Spain. It is a partnership between Spain, Mexico and the University of Florida. Main science drivers for the GTC are image quality, operational efficiency and reliability. First light is planned for mid-2005. The GTC Project

In order to understand the heating of the solar corona it is crucial to obtain empirical information on the magnetic field in its lower boundary (the transition region). To this end, we need to measure and model the linear polarization produced by scattering processes in strong UV lines, such as the hydrogen Lyα line. The interpretation of the

Spectroscopy has shown the presence of CN band dichotomy and Na-O anticorrelations for 50-70 per cent of the investigated samples in the cluster 47 Tuc, otherwise considered a `normal' prototype of high-metallicity clusters from its photometric analysis. These anomalies are also found in main-sequence stars, suggesting that a consistent second

With ACS-HST images we produced continuum subtracted photometric maps in Hα for the galaxies M51 and NGC 4449. From the Hα luminosity (L), equivalent radius (R) and coordinates of the HII regions with respect to the galaxy centers (over 2000 regions for M51, over 200 regions for NGC 4449), we derived the mean luminosity weighted electron density,

We present a detailed study on the surface composition of 2003 EL61. We use visible and near-infrared spectra of 2003 EL61 obtained for more than three consecutive hours covering more than 80% of the rotational period, in the Telescopio Nazionale Galileo and William Herschel Telescope, sited in the Observatorio del Roque de los Muchachos. First we