Projection device for planetaria

摘要

The invention relates to a projection device for planetaria for generating cycles of phases in representations of the moon and planets. The aim of the invention is a realistic reproduction of this cycle of phases. The object of simplifying the diaphragm drive mechanism required is achieved by enabling at least one diaphragm, which in accordance with the invention is attached to at least one tensioned, endless guide belt, to be inserted into the projection beam path. It is advantageous to mount a plurality of diaphragms having mutually differing shapes and sizes on the guide belt. It is favourable for the stability of the system if the diaphragms are mounted between two synchronously running guide belts. The invention differs from the known technical solutions in that the diaphragms are guided continuously and without vibration through the projection beam path.