  We demonstrate how the elementary amplitudes $\gamma N\to \Psi N$, the
amplitude of the nondiagonal $J/\psi N\Leftrightarrow \psi' N$ transition, and
the total $J/\psi N$ and $\psi' N$ cross sections can be determined from
measurements of the coherent $J/\psi$ and $\psi'$ photoproduction off light
nuclei at moderate energies. For this purpose we provide a detailed numerical
analysis of the coherent charmonium photoproduction off silicon within the
generalized vector dominance model (GVDM) adjusted to account for the physics
of charmonium models and color transparency phenomenon.
