Computing period integrals of rigid double octic Calabi-Yau threefolds with Picard-Fuchs operator

We present a method for numerical computation of period integrals rigid Calabi-Yau threefold using Picard-Fuchs operator one-parameter smoothing. Our gives possibility computing the lattice double octic without any explicit knowledge its geometric properties, employing only simple facts from theory Fuchsian equations and computations in MAPLE with library differential equations. As surprising consequence we also get approximations additional related to singular (nodal) model considered threefold.