We present low resolution maps, of a 4' × 0'.5 region, of comet Halley, in photometric bands J and K, a central scan in the H band and JHKL photometry taken with the 1.5 m Sanchez-Magro Telescope of the Instituto de Astrofisica de Canarias. We obtain central and integrated magnitudes and colours and discuss its variation with distance from the

The accelerated Lambda iteration method is used to obtain better theoretical profiles of He II in hot stars by considering more levels and Stark broadening in the statistical equilibrium equations. It is found that an appropriate He II model atom must consist of 14 non-LTE levels and that Stark broadening must be included for all lines with upper

A complex kinematical structure is inferred from the analysis of high resolution spectra of the nuclear region of the galaxy NGC 6946. The spatial resolution of the observations allowed the authors to resolve a dynamically inhomogeneous area of approximately 10 arcseconds in diameter, very close to the centre of the galaxy. Within this region the

PARTIENDO DE UNA OBSERVACION EN EL CUMULO DE COMA AFECTUADA POR EL SATELITE EXOSAT DURANTE SU FASE DE VERIFICACION DE CARACTERISTICAS SE PUDO OBSERVAR LA GRAN DENSIDAD DE FUENTES DE RAYOS X DESCONOCIDA EN ESE CAMPO. A PARTIR DE ESTOS RESULTADOS PREVIOS SE OBTUVO TIEMPO PARA EFECTUAR OTRA OBSERVACION MAS LARGA EN LA MISMA REGION EN 1985. EL ANALISIS

EN ESTE TRABAJO SE REALIZA UN ANALISIS DE LA ESTRUCTURA HIPERFINA DE LOS MODOS ACUSTICOS SOLARES A PARTIR DE DATOS OBTENIDOS CON UN ESPECTROMETRO POR SCATTERING RESONANTE EN PERIODOS ESTIVALES DE OBSERVACION A LO LARGO DE CASI UN CICLO DE ACTIVIDAD SOLAR. A PARTIR DE ESTE ESTUDIO SE OBTIENE EL TIEMPO DE VIDA DE LOS MODOS ACUSTICOS SOLARES DE BAJO

CCD UBV photometry of 2279 stars in Sextans A is presented. Differences with the photometric scales of Sandage and Carlson (1985) and Hoessel et al. (1983) are discussed; recalibration of the Sandage and Carlson data for Cepheids in Sextans A results in a smaller value for the distance modulus, μ = 25.6. A similar value for the distance modulus is