Planetarium and projection apparatus for same

A projection device for use in a planetarium having a plurality of projection apparatus, said projection device comprising an independent unit which includes:

• a projector for projecting a star or other body;
• an axis for rotatably supporting said projector;
• drive means for rotating said axis;
• and
• a controller for said projection device which is built into said projection device, said controller comprising:
• computing means for calculating data relating to an amount of rotation of said axis in accordance with inputted date;
• and
• control means connecting said computing means to said drive means for controlling said drive means to rotate said axis based on the data calculated by said computing means.

A planetarium comprising:

• a dome,
• a host computer,
• input means for inputting time and date data and viewer coordinates data to said host computer, said host computer calculating a date according to the Julian calendar corresponding to the date and time data input via said input means,
• a star field projection apparatus for projecting a star field on said dome, and
• a plurality of supplemental projectors for projecting planets and the like on said dome,
• wherein said star field projection apparatus incorporates a first computing means connected to said host computer for calculating data relative to a positional orientation of the star field projection apparatus based on said Julian calendar date and said viewer coordinates data from said host computer, and first control means connected to said first computing means for controlling a positional orientation of said star field projection apparatus based on the data calculated by said first computing means;
• and
• wherein each of said plurality of supplemental projectors incorporates a second computing means connected to said host computer, each of said plurality of second computing means being built-in to a respective one of said plurality of supplemental projectors for calculating data relative to the positional orientation of its respective supplemental projector based on said Julian calendar date and said viewer coordinates data from said host computer, and a second control means connected to each of said second computing means for controlling a positional orientation of its respective supplemental projector based on the data calculated by said second computing means.