Mapping clusters of galaxies with a stratospheric balloon experiment

We describe the scientific rationale and the preliminary calibrations of the OLIMPO experiment: a 2.6 in stratospheric balloon borne telescope, to be flown in 2008 in a long duration circumpolar flight. One of the main goals of the experiment is to map with high sensitivity and resolution at.,,mm and submm, wavelengths the Sunyaev-Zel'dovich effect in many clusters of galaxies, both in the Northern and in the Southern hemisphere.