From high-resolution CCD images of granulation obtained at the Swedish Solar Tower of the Observatorio del Roque de los Muchachos at different positions on the solar disk, mean bi-dimensional spatial power spectra have been obtained at each position and restored following the method proposed by Rodriguez Hidalgo et al. (1990). The variation with

High-resolution CCD images are presented of a sample of spiral galaxies, in infrared photometric bands, obtained at the Cassegrain focus of the 1 m Jacobus Kapteyn Telescope, La Palma. A decisive advantage of the linearity in these images is that a reliable separation of the light from bulge and disk can be effected. Possible applications of the

A set of series of spectra of high spectral resolution corresponding to the same umbra on several days, is used to study the oscillations related to evolution of the two main dark cores of it. Differences in the behavior of each core and an evolution in the power spectra not related with the external appearance of the spot are detected. A quite

A continuum intensity-magnetic field distributions are presented for a decaying sunspot. It is shown that a very simple model accounts for the observed correlation. The Wilson depression is determined.

The diagnostic method proposed by Landi Degl'Innocenti and Landolfi (1982), based on the observation of circular polarization, has been generalized to derive the thermodynamic properties of unresolved magnetic elements in the solar atmosphere. The final aim is to derive the height dependence of several parameters of the flux tube atmosphere. A

Recent observational and theoretical investigations of the sun and sunlike stars and of galactic structure and evolution are discussed in reviews and reports. Topics addressed include sunspot-group decay rates for 1874-1976, photometry and spectroscopy of solar granulation along the polar axis and equator, the quiescent radio emission of RS CVn