The work on construction and operation of automated systems for collection and processing astrometric and meteorological information and also of automated television systems with remote control have placed before us a number of fundamental difficulties in that hundreds of correct solutions to these problems require a systematic approach.

The most suitable cybernetics-mathematical composite for solving the problems of astronomical refraction may become the so-called hybrid-expert systems — a union of traditional expert systems with calculation-logical ones. In these systems logical-linguistic models are used together with mathematical ones.

The basic problem of ARA-C consists in obtaining a model of the environment in which light propagates and also to give a notion of interaction between electrons (environment) and photons (light).

It is proposed to use in this system a model of light interaction with environment built up on special formalisms of artificial intellect (logical-linguistic model). The basic principal in hybrid-expert system ARA-C operation must be mathematical modelling and calculation experimentation. In the proposed hybrid-expert system knowledge is presented on three levels—object, mathematical and programmed. Functioning of the lower levels of ARA-C is connected with formulation of the calculation problems. A calculation problem presented to a technical model determines a partial order on a twopart column of mathematical correlations.