Aims: We study the properties of solar granulation in a facular region from the photosphere up to the lower chromosphere. Our aim is to investigate the dependence of granular structure on magnetic field strength. Methods: We used observations obtained at the German Vacuum Tower Telescope (Observatorio del Teide, Tenerife) using two different

The Local Group galaxies enable us to study the impact of metallicity on the structure and evolution of massive stars through spectroscopic analyses. However, color-based target selection for spectroscopy (in absence of known spectral types), though relatively successful, usually produces lists dominated by B-type modest-mass stars. We have

We describe a simple step-by-step guide to qualitative interpretation of galaxy spectra. Rather than an alternative to existing automated tools, it is put forward as an instrument for quick-look analysis and for gaining physical insight when interpreting the outputs provided by automated tools. Though the recipe is for general application, it was

The seemingly un-magnetized part of the solar surface is not really un-magnetized. It is occupied by magnetic structures producing low polarization which, therefore, escape detection in traditional measurements. Since most of the solar surface belongs to this category, the quiet Sun magnetic fields can easily carry most of the magnetic flux and

This paper presents the results of an investigation of the quiet Sun's magnetic field based on high-resolution infrared spectropolarimetric observations obtained with the Tenerife Infrared Polarimeter (TIP) at the German VTT of the Observatorio del Teide. We observed two very quiet regions at disc centre. The seeing was exceptionally good during

We present heliocentric radial velocities for a large number of emission lines covering all the optical spectral range for two slit positions of the Galactic H Ii regions M 42 and M 17 and one slit position of M 8. We obtain a fairly similar relation between the heliocentric velocity and the ionization potential of the ions in all the observed slit