We are carrying out a study of the physical parameters and excitation of low-ionization structures (LIS) in planetary nebulae (PNe). Since the optical morphology and kinematics of the LIS and the main components (rims, shells and haloes) of our sample were studied previously, our main goal now is to search for: i) the density contrasts between jets

We report TIMMI2 diffraction-limited mid-IR images of the multipolar PPN IRAS 16594-4656. By using the Lucy-Richardson deconvolution algorithm we recover a two-peaked morphology in the innermost region at 8.6 μm and 11.5 μm. We interpret the observed mid-IR structure as the detection of the two limb-brightened peaks indicating the presence of a

We present a new estimate of the mass of the Milky Way, making use of a large sample of 955 field horizontal-branch (FHB) stars from the Early Data Release of the Sloan Digital Sky Survey. This sample of stars has been classified on the basis of an automated analysis approach, in combination with other methods, in order to obtain estimates of the

We have imaged ˜ 1 deg2 in the V-band in the direction of the Hercules cluster (Abell 2151). The data are used to compute, for the first time, the luminosity function (LF) of galaxies in the cluster down to the dwarf regime (Mlim ˜ -13.85 ). The global LF is well described by a Schechter function (Schechter 1976) with best-fit parameters α = -1.30

We are conducting a study on the energetics and dynamical evolution of the final stages of intermediate and massive stars. Our project includes the study of the ionization structure of the haloes of MSPNe and WRNe, and the detection of a possible shock-heated gas component. We present here the set of observations so far obtained, and preliminary

The DIMM is a widely accepted and often used instrument for seeing measurements. Nevertheless, its incorrect use may give rise to errors in seeing values. A detailed analysis of the parameters involved in the seeing calculation is being undertaken and the effect of saturation of the spots in particular is analyzed in this contribution. Our results