  Observations of the X-ray band wavelength reveal an evident ellipticity of
many galaxy clusters atmospheres. The modeling of the intracluster gas with an
ellipsoidal $\beta$-model leads to different estimates for the total
gravitational mass and the gas mass fraction of the cluster than those one
finds for a spherical beta-model. An analysis of a recent Chandra image of the
galaxy cluster RBS797 indicates a strong ellipticity and thus a pronounced
aspherical geometry. A preliminary investigation which takes into account an
ellipsoidal shape for this cluster gives different mass estimates than by
assuming spherical symmetry. We have also investigated the influence of
aspherical geometries of galaxy clusters, and of polytropic profiles of the
temperature on the estimate of the Hubble constant through the
Sunyaev-Zel'dovich effect. We find that the non-inclusion of such effects can
induce errors up to 40 per cent on the Hubble constant value.
