We discuss the reduction strategy adopted to perform the relative and the absolute calibration of the Wide Field Imager (WFI) available at the 2.2m ESO/MPI telescope and of the Mosaic Camera (MC) available at the 4m CTIO Blanco telescope. To properly constrain the occurrence of deceptive systematic errors in the relative calibration we observed

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Recently a tight correlation between the bulge velocity dispersion and the galaxy circular velocity has been found for a sample of spiral galaxies (Ferrarese 2002). Since bulge velocity dispersion and circular velocity are related to the masses of the central black hole and dark matter halo respectively, the correlation between velocity dispersion

We want to study the characteristics and the physical extent of the old populations in a sample of Local Group galaxies in different environments, from the dSph satellites in the halo of M31 to the isolated dIrr galaxies and to the haloes of M31 and M33 themselves. For this purpose, we plan to adopt RR Lyraes as stellar tracers. We need to obtain a