Direct measurement of intersection angle of invariant manifolds for area preserving mappings

Intersection angles of stable and unstable manifolds for area preserving mappings are numerically calculated by extremely accurate computation. With the use of multiprecision library the values of angle as small as 10^{-400} are obtained. The singular dependence of the angle on the magnitude of hyperbolicity is confirmed. The power-law type prefactor with Stokes constant is also in good agreement with analytical estimation.