  We analyze the window functions for the spherical harmonic mode estimators of
all--sky, volume limited surveys considering evolutionary effects along the
past light--cone which include the deviation of the distance scale from a
linear relationship with redshift, linear peculiar velocity corrections, and
linear evolution of the density perturbations. The spherical harmonic basis
functions are considered because they correspond most closely to the symmetries
of typical survey geometries and of the light--cone effects we consider. Our
results show substantial broadening of the windows over that expected by
ignoring light--cone effects, indicating the difficulty of measuring the power
spectrum independently from cosmology. We suggest that because of light--cone
effects, deep redshift surveys should either be analyzed in conjunction with
CMBR data which determines the cosmological parameters, or by using a Bayesian
likelihood scheme in which varying cosmological parameters and a simple
parameterization of the primordial power spectrum are assumed as the priors, so
that observed data can be mapped from redshift to real space. The derived power
spectrum can then be compared to underlying models of fluctuation generation
and growth in structure formation to evaluate both these models and the
cosmological priors.
