During the last years, inversion techniques have become one of the most powerful tools to obtain, from spectropolarimetric data, the stratification of physical quantities (temperature, pressure, velocity fields, magnetic field, etc.) describing different structures in the solar atmosphere. The SIR code (Stokes Inversion based on Response functions)

We present data from the Infrared Space Observatory (ISO) of a complete set of Seyfert galaxies (Seyfert 1 and Seyfert 2) in a wavelength range seldom explored so far. These data allow a detailed study of the far IR Spectral Energy Distribution of these sources.

We present, for the first time, three dimensional (3D) radiative transfer (RT) results with realistic atomic models (multilevel) and without using the local thermodinamical equilibrium approximation (non-LTE). We have developed a new code based on efficient iterative methods (Trujillo Bueno, and Fabiani Bendicho 1995; Fabiani Bendicho, Trujillo

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The characteristics of OSIRIS (Optical System for Imaging and low-Resolution Integrated Spectroscopy), an instrument for imaging and low resolution spectroscopy proposed for the GTC 10m telescope, are described. OSIRIS is a multi-purpose instrument that incorporates in a "classical design" several innovations, already tested in 4m-class telescopes

Narrow-band CCD images of 209 axially symmetrical planetary nebulae (PNe) have been examined in order to determine the orientation of their axes within the disc of the Galaxy. The nebulae have been divided into the bipolar (B) and elliptical (E) PNe morphological types, according to the scheme of Corradi & Schwarz. In both classes, contrary to the