The projectors in a planetarium should not project into the auditorium, in order to prevent the spectators from being dazzled. Screens are used for this purpose, which align themselves depending on the position of the projector in question. The bearings used for the screens must be maintenance and lubricant-free, as they come into direct contact with optical elements. They must also withstand temperatures of over 90° C in continuous operation. The plain bearing material iglidur® Z is used here. What is particularly smart: a regular bearing is divided into rings of the required size, thus reducing the overall costs of this solution even further.