  We study the perturbations of a relatively close third star on a tidally
distorted eccentric eclipsing binary. We consider both the observational
consequences of the variations of the orbital elements and the interactions of
the stellar rotation with the orbital revolution in the presence of
dissipation. We concentrate mainly on the effect of a hypothetical third
companion on both the real, and the observed apsidal motion period. We
investigate how the observed period derived mainly from some variants of the
O-C relates to the real apsidal motion period. We carried out both analytical
and numerical investigations and give the time variations of the orbital
elements of the binary both in the dynamical and the observational reference
frames. We give the direct analytical form of an eclipsing O-C affected
simultaneously by the mutual tidal forces and the gravitational interactions
with a tertiary. We also integrated numerically simultaneously the orbital and
rotational equations for the possible hierarchical triple stellar system AS
Camelopardalis. We find that there is a significant domain of the possible
hierarchical triple system configurations, where both the dynamical and the
observational effects tend to measure longer apsidal advance rate than is
expected theoretically. This happens when the mutual inclination of the close
and the wide orbits is large, and the orbital plane of the tertiary almost
coincides with the plane of the sky. We also obtain new numerical results on
the interaction of the orbital evolution and stellar rotation in such triplets.
The most important fact is that resonances might occur as the stellar
rotational rate varies during the dissipation-driven synchronization process...
