We present a method that we developed to discern where the optical microvariability (OM) in quasars originates: in the accretion disk (related to thermal processes) or in the jet (related to non-thermal processes). Analyzing nearly simultaneous observations in three different optical bands of continuum emission, we are able to determine the origin

We present deep, accurate, and homogeneous multiband optical (U, B, V, I) photometry of the Carina dwarf spheroidal galaxy, based on more than 4000 individual CCD images from three different ground-based telescopes. Special attention was given to the photometric calibration, and the precision for the B, V, and I bands is generally better than 0.01

Available from the Minor Planet Center.

Available from the Minor Planet Center.

We investigate 10 QSO host galaxies at 1

We present the results of the search for candidate Planetary Nebulae interacting with the interstellar medium (PN-ISM) in the framework of the INT Photometric Hα Survey (IPHAS) and located in the right ascension range 18-20 h. The detection capability of this new Northern survey, in terms of depth and imaging resolution, has allowed us to overcome