  In this paper we examine magnitudes of quasars as a function of redshift in
different frequency ranges (u,g,r,i,z). We show that on the smoothed curves
mag(Z) in frequency ranges u,g,r there are characteristic features both similar
for all the curves and different for different curves. At Z<2 all the curves
have practically the same form with two characteristic sections of the negative
slope, at Z>2 the forms of the curves significantly differ. The nature of these
differences can be interpreted as an influence of Lyman-alpha absorption. Then
we analyze the dependencies on redshift of the magnitudes averaged over the sky
in the range r, free fromLyman-alpha absorption effect, for galaxies and
quasars and show that as for quasars and for galaxies the dependencies of
average magnitudes on Z have a nature of converging oscillations with areas of
negative slope, corresponding to increase of apparent luminosity with
increasing of the distance. We calculate the corresponding values of the
average absolute luminosities for the flat space and for different variants of
the LambdaCDM model. In all cases they increase with the growth of the
redshift. When the redshift increases from 0.02 to 2 then average radiation
power of galaxies increases by thousands times. Such changes appear to be
impossible which leads us to the assumption that these results are related to
the used calculation methods and the features of the metric tensor underlying
of the standard cosmological model. In the modified cosmological model which
built on the metrics obtained with the considering the non-zero value of the
differential of scale factor, appear features that are missing in the standard
model, including the effect of increase of the apparent luminosity with the
increase of distance. Calculation allows obtaining a curves close to
dependencies of average magnitudes on redshift issuing from observation data.
