The Fraunhofer Pattern of а Wave Field Generating by a System оf Coherent Emitting Point Sources

The problem of description a wave field generating by system coherent point sources is considered. This discussed for two well-known approximations, the Fresnel and Fraunhofer patterns, correspondingly. It shown, that validity both approximations has to contain dimensionless small parameters. First them parameter area second one corresponding observation area. In framework pattern Laue conditions diffraction maximums periodic arranged derived.