We present new BV photometry for 6564 stars in the field of the globular cluster NGC 6366, using a wide field CCD camera at the prime focus of the Isaac Newton Telescope (INT 2.5m). The mean internal accuracy of the present V magnitudes and (B-V) colours ranges from 0.005mag for the stars at the top of the Red Giant Branch to 0.07mag for the

We have obtained near-infrared observations of some of the faintest objects so far known towards the Pleiades young stellar cluster, with the purpose of investigating the sequence that connects cluster very low-mass stars with substellar objects. We find that infrared data combined with optical magnitudes are a useful tool to discriminate cluster

We present a new, fast and easy to use NLTE line formation code for ``unified atmospheres'' with spherical extension and stellar winds, developed for the (routine) spectroscopic analysis of luminous blue stars, covering the spectral range from ``A'' to ``O'' and including central stars of planetary nebulae. The major features of our code are: Data

We present the results of applying a new chemo-evolutionary stellar population model, developed in a previous paper, to new high-quality observational data of the nuclear regions of two representative elliptical galaxies and the bulge of the Sombrero galaxy. Here we fit in detail ~20 absorption lines and six optical and near-infrared colors

We present a comparison between images of comet C/1995 O1 (Hale-Bopp) obtained from 12 March to 9 May 1997, with two telescopes of the Observatorio del Teide (IAC, Tenerife, Spain) in visible (Johnson-V filter) and three near-infrared narrowband filters (Brγ (2.166 μm), CO (2.295 μm), and Kcon (2.260 μm)). No significant differences are observed

We present the first results of our program of spectroscopic observations with orbital phase resolution of short-period active binaries. We have collected simultaneous data in the lines Hα, Hβ, and the infrared triplet (IRT) of Ca II (8498 and 8542 A). In this paper we discuss the methods used to analyze the spectra and describe the results