With the use of data from COBE, IRAS and the Two-micron Galactic Survey (TMGS), we examine the effect on star counts and surface brightness maps of the position of the Sun above the Galactic plane and of a possible tilt between the b=0 deg plane and the plane of the old disc (to a distance of 3 or 4 kpc from the Sun). We find that the Sun is 15.5+/

New grids of stellar evolutionary models are presented for a wide range of initial hydrogen content around the solar composition. These compositions are (X, Z) = (0.80, 0.02), (0.70, 0.02) and (0.60, 0.02). Recent OPAL opacities with LS coupling and Grevesse composition were adopted, and Alexander's tables were used for lower temperatures. We

Not Available

The results reported in this paper concern two delta Scuties in the Praesepe cluster, namely BN Cnc and BU Cnc, observed during the 1992 STEPHI 4 campaign. Five and six frequency peaks, respectively, were recorded as a result of the campaign. In this work, an attempt is made to identify these frequency peaks as pulsation models, based on stellar

We present near-infrared (JHK) imaging of the Seyfert 2 galaxy NGC 5252, taken with the IRAC2 array on the 2.2m telescope at ESO, La Silla. The unresolved and galactic components to the nuclear emission are separated by a multicomponent fitting of the light profiles in the optical and near-infrared bands. The nuclear flux in a 3" aperture is found

Accurate, absolute, and reproducible measurements are the expected qualities of any instrument. A differential image motion monitor (DIMM) is presented which assesses astronomical seeing with those requirements. It has been designed (with collaboration of the staff of the Department d'Astrophysique de l'Universite de Nice and the Instituto de