Determining Top Quark CP Violating Dipole Couplings from e^+e^-to tbar t

We show how to determine the electric and weak dipole moments of the top quark simultaneously and independently from $e^+e^-\to t\bar t$ at $\sqrt{s}=500$ GeV NLC. To obtain the best accuracies with which the dipole moments can be measured, we apply the optimal observables to extract the CP violating effects and consider only purely hadronic, hadronic-leptonic final state events. Results with left- and right- handed longitudinal polarized as well as unpolarized electron beams are given. We find that with $50fb^{-1}$ integrated luminosity, the dipole moments can be measured to the accuracy of $10^{-18}~e~cm$.