The Star Theater

The instrument in the center of the Morehead Planetarium Star Theater is a Zeiss Model VI Planetarium Star Projector. It projects some 8,900 fixed stars down to magnitude 6.5, along with 17 star clusters and nebulae. The fixed star slides in 32 fixed star projectors are chromium evaporated glass plates, with holes 0.023 to 0.33mm in diameter photochemically etched into the chromium. The main star lamps were originally 1350-watt mercury-cadmium capillary arc lamps costing approximately $1000.00 apiece but have since been modified to use 1000-watt General Electric mercury-vapor lamps (exactly like those used in ordinary street lights except of much higher wattage) at a cost of a mere $35.00 per bulb.

A Zeiss Model II Star Projector was in place when the building opened on May 10, 1949. This Model II had previously been installed in Stockholm and Gothenburg, Sweden. The star projector was converted to a Model III in 1959, and the present Model VI was installed in 1969. The new star projector arrived on January 9, 1969 in 43 shipping crates consisting of 15,000 pounds of equipment. Two German technicians sent by the Zeiss company assembled and tested the machine. The installation took about three months. The star projector itself weighs 5,000 pounds.

Scattered about the theater are 53 slide projectors for displaying images among the stars, as well as over a hundred special effects. There are also two video projectors aimed at the dome.

In January of 1984, to enhance productions, the Morehead Planetarium closed while the Zeiss instrument was linked to the MC-10A Media Control System, making ours one of the very few completely automated Zeiss facilities in the world. There are only six other Zeiss Model VI Star Projectors in the United States. Our star projector was originally installed at a cost of $250,000. The cost of replacing the star projector today would be about two million dollars. In 1994, the media control system was updated to include the East Coast Control Systems Hercules system, which features a more sophisticated computer which can handle more projectors and special effects than before. The Hercules system also adds to the ease and speed of preparing and presenting automated star shows.

The Star Theater can seat 300 people under a 68-foot diameter dome of perforated, stainless steel. The dome is painted with a matte white paint to regulate the reflectivity of the star field. The top of the dome is 43.5 feet above the floor at the center of the theater. The dome contains approximately 15 million holes, each .081 inches across. The screen is about 9% void, meaning that the holes take up about one-twelfth of the surface area of the dome. This allows some of the special effects equipment to be placed behind the dome and still be seen.