Eidour anion
Screening at the English Opera House , London 1817
An eidour anion is a precursor to today's planetariums . It was developed in 1770 by the English inventor Adam Walker . It is a kind of transparent orrery , which is illuminated on the back with a projector in order to show the movement of the heavenly bodies on a screen.
Mostly the eidour anion was used for entertainment. During the demonstration, music was read and played.