A 90 minute time series of high spatial resolution white-light images of solar granulation, obtained at the Swedish Vacuum Solar Tower (Observatorio del Roque de los Muchachos, La Palma), was analyzed to study how the physical properties of the granules changed with size. The observational material was corrected for global motions and for the

Monitoring of the near-nucleus activity of C/1995 O1 (Hale-Bopp) began in Teide Observatory in August 1995. During 1996 the comet was observed on 72 nights between March 26 and November 13. A permanent fan structure was observed towards the north during the whole period of observation. The position angle of the axis of this fan was measured and its

Dwarf irregular (dIr) galaxies are frequent targets of young stellar populations research. But less attention has been devoted to their intermediate-age and old stars. For galaxies at moderate distances (more than ~ 10 Mpc) the study of these populations must rely on population sinthesys techniques that provide just crude estimates. For nearby

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An 8 month monitoring campaign on the Seyfert 1 galaxy Fairall 9 has been conducted with the International Ultraviolet Explorer in an attempt to obtain reliable estimates of continuum-continuum and continuum--emission-line delays for a high-luminosity active galactic nucleus (AGN). While the results of this campaign are more ambiguous than those of