The sales promotion of the planetarium is a marketing problem. Program arrangements must take this into account. Marketing is not exclusively a tool to obtain a maximum profit: marketing methods can control the exchange problems between the public and the nonprofit planetarium. The planetarium produces a service. This service must be distributed to the public. The public must know that the planetarium distributes a special service.

The public visits the planetarium during leisure time. (One exception — the school classes — is not considered here.) Therefore one marketing problem of the planetarium is to sell its service as recreational value.

The leisure time activities of the public can be divided into 10 categories. These categories contain the basic patterns and needs of the public. The content of the public planetarium performances must try to cover the leisure-time categories. The communication windows of the public can only be reached by simplifying astronomical facts.