How to get Airy disc from Airy pattern

Airy pattern is formed by diffraction of a plane wave through a circular aperture in the far field with certain side lobes. It is shown that Airy pattern can be truncated at the first dark ring by a circular aperture to pick up the center spot (called Airy disc) without causing additional diffraction fringes, even in the very far field. This may be called zero field truncation technique. And is very useful in practice, for example, as a good quality optical source.