Many complex organic molecules and inorganic solid-state compounds have been observed in the circumstellar shell of stars (both C-rich and O-rich) in the transition phase between Asymptotic Giant Branch (AGB) stars and Planetary Nebulae (PNe). This short (~102-104 years) phase of stellar evolution represents a wonderful laboratory for

We present the results of a five-month spectroscopic monitoring campaign of two radio loud quasars, PKS 1217 + 023 and PKS 1302 - 102. There is a pronounced lack of variability in 1302 - 102 apart from a possible small change in the continuum level near the end of the monitoring period, but 1217 + 023 underwent a 20 percent continuum decrease in

We present a complete study of the morphology of post-Asymptotic Giant Branch (post-AGB) stars. The post-AGB stage is a very short evolutionary phase between the end of the AGB and the beginning of the Planetary Nebula (PN) stage (between 100 and 10,000 yrs). Post-AGB stars do not show variability and are not hot enough to fully ionize the hydrogen

We present the first strong-lensing study of the mass distribution in the cluster MS 2053-04 based on HST archive data. This massive, X-ray luminous cluster has a redshift z=0.583 and is composed of two structures that are gravitationally bound to each other. The cluster has one multiply imaged system composed of a double gravitational arc. We have

New visual light curves and infrared multi-epoch photometry are presented for a sample of AGB-stars spectroscopically observed with ISO. While the ISO work is or will be presented elsewhere, the aim of this paper is to give an overview of the properties of the light change of the objects. This information is crucial for the interpretation of the

This paper analyses the various ways of carrying out near IR multi-object spectroscopic studies in space. We show that ground-based observations would have limited results except in the 1-1.5 micrometers wavelength where large telescope of the 8m class would be approximately equivalent to a 1m in space. Beyond 2m, even an instrument such as the