The Owl Nebula (NGC 3587) is a double shell nebula. An additional faint halo is recently found in interference filter CCD images (Kwitter, Chu, & Downes 1992, in IAU Symp. 155). To confirm and to determine the physical nature of this halo, we have obtained spectra of the Owl Nebula with the IDS spectrograph on the INT 2.5m telescope at La Palma

SE PRESENTA UN ESTUDIO OBSERVACIONAL DE PROCESOS DE FORMACION ESTELAR EN GRAN ESCALA EN GALAXIAS ESPIRALES CON BRAZOS BIEN DEFINIDOS. SE HA OBSERVADO NOC 4321 EN 21 CM HI, J=1 0 CO Y H Y USADO DATOS DE LA LITERATURA PARA M51. DE UN ANALISIS DE LA EFICIENCIA DE FORMACION DE ESTRELLAS MASIVAS (MSFE) SIGUIENDO LOS BRAZOS PRINCIPALES DE ESTAS GALAXIAS

On the basis of a sample of Virgo cluster galaxies in a larger set of heterogeneous literature data, it is shown that ellipticals, early-type dwarfs, and bulges of S0s and of spirals form two distinct families in the plane of the effective parameters, R(e) and mu(e). The 'ordinary' family is composed of all galaxies fainter than MB of about -19.3

We present a second-order analytical expansion of null equatorial geodesics in the Kerr metric. The equations developed are applied to the study of light transit in compact binary systems. We show that the effects arising from path bending have a significant influence on the computed time delays, even at first order of approximation in the

An analysis of about 27 h of fast photometry of the cool ZZ Ceti white dwarf PG2303+243 reveals (1) the presence of many modes (as many as 22), some of them of low enough amplitude to have escaped previous detection, and (2) a short time scale (less than 10 d) drastic variation in amplitude. A preliminary identification of the modes observed in