We have observed the cosmic microwave background (CMB) in three regions of sky using the Very Small Array (VSA) in an extended configuration with antennas of beamwidth 2° at 34 GHz. Combined with data from previous VSA observations using a more compact array with larger beamwidth, we measure the power spectrum of the primordial CMB anisotropies

In this paper we present the Johnson-Cousins UBVR CCD photometry of the stars in King 2, an old open cluster towards the galactic anticenter. We have obtained the colour-magnitude diagram, the colour excess, the reddening, an estimate of the metallicity, and the distance modulus. The comparison of the observational colour-magnitude diagram with the

En la tesis se presentan los resultados de un estudio comparativo de la formación estelar que tiene lugar en dos galaxias espirales distintas: una floculenta (NGC 4395) y una de gran diseño (NGC 5457). Para ello se obtuvo una serie de imágenes en banda estrecha en diferentes líneas de emisión de las regiones HII. De esta forma no sólo se obtuvo

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Jupiter-family comets are of particular interest for several reasons, including the fact that they are the most accessible to spacecraft. These comets also present the best opportunities to study cometary nuclear surfaces. The characterization of cometary nuclear surfaces and their comparison with those of related populations such as extinct comet

We present Doppler Images of the RS CVn binary system HR 1099 (V711 Tau) from spectra taken in two different sites, KPNO and MSO, during the MUSICOS 1998 campaign. Contemporaneous APT photometry is used to constrain the Doppler Images. The resulting maximum entropy reconstructions based on the least-squares deconvolved profiles, derived from ~ 2000