  We present an analytical method to extract observational predictions about
non linear evolution of perturbations in a Tolman Universe. We assume no a
priori profile for them. We solve perturbatively a Hamilton - Jacobi equation
for a timelike geodesic and obtain the null one as a limiting case in two
situations: for an observer located in the center of symmetry and for a non -
centered one. In the first case we find expressions to evaluate the density
contrast and the number count and luminosity distance vs redshift relationships
up to second order in the perturbations. In the second situation we calculate
the CMBR anisotropies at large angular scales produced by the density contrast
and by the asymmetry of the observer's location, up to first order in the
perturbations. We develope our argument in such a way that the formulae are
valid for any shape of the primordial spectrum.
