Technical Details

colorful laser lights
Planetarium - Technical Details

Planetarium Laser Projector

As the centennial of the first modern planetarium draws near, advances in technology have transformed these star-theaters that help connect viewers with their place in the Universe.

Since 1959, the Kalamazoo Valley Museum has been able to share the wonders of the universe with myriad technologies from optical-mechanical systems, slide projectors, the first digital projection systems, and finally to full-dome immersive video. With each iteration of new technology that has been employed, our patrons have also been able to visualize both the night sky overhead and make connections to their natural world.

In the spirit of updating the KVM Planetarium and maintaining a quality experience for our audiences, the planetarium has recently replaced its sound system, added new LED lights, and upgraded the “star-projection” system to the latest version of Digistar. These tools combined will allow our presenters to share not only the night sky but will also immerse audiences into a variety of full-dome experiences.

Each theater seat is equipped with five-button keypad providing opportunities to interact with many of the shows. Also equipped with a Microsoft Kinect ™ interface, some visitors may be given an opportunity to take control of a segment of the show.

The slide projectors, video projectors, special effect projectors and existing star projector were all replaced by a very special projector located in the middle of the room. This projector is a full dome video graphics system called a Digistar 4. It covers the entire screen with spectacular images beyond anything shown here before.

The star projector is a black box with a fisheye lens in one corner. It uses a red, green and blue laser as light sources. The light is combined into a single line that is reflected by a grating light valve, a chip with reflective ribbons that control the intensity of the color for 4096 sections of the line. The line is swept across the dome 60 times a second by a scanning mirror, producing an image 4096 x 4096 pixels across.

Evans & Sutherland

Digistar 4 projector

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The theater screen is a 50 foot diameter hemisphere suspended from the ceiling on chains. It is made up of 196 curved perforated aluminum panels riveted to a tubular metal skeleton. Holes in the aluminum panels allow air to flow in the theater and sound to pass through from the speakers that are mounted on the back of the dome.

Photograph: The Planetarium's Dome

The planetarium dome lighted from behind

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Interactive Keypads

In addition to the audio-visual elements, the Planetarium features an interactive control system. Each seat is equipped with a five button keypad which can be used to answer questions or select program segments.


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Equipment Racks

Sources for the audio and video materials and controllers for the keypads are located in a control room beside the theater. Signals from the control room racks run to controllers throughout the theater. Some controllers run slide projectors, others operate special effects.

equipment racks

The large blue racks house the audio amplifiers and special effect controllers, the small rack holds the 10 computers of the Digistar 4 system.

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Automation System

The Digistar 4 host computer sends a time signal to synchronize the Sky-Skan Spice automation computer with the show soundtrack. Now, the automation system only controls special effects, the room lights and the sound levels.

Sky-Skan Spice Automation

Projection Galleries

The projection galleries are now empty. The new full-dome LASER projection system does everything the collection of slide and video projectors did in the past. Around the dome there are still a few special effect projectors for snow, cloud effects, and effects that do not translate well to video.

Sound System

The planetarium has a five channel surround sound system. The system is made up of three speaker clusters at the front left, top center, and front right of the theater. Each of these clusters has three speaker sets. Additional speaker sets are located at the rear of the theater, on the left and right sides. Two large subwoofer speakers are located behind a grill at the front of the theater.

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Production Areas

Many of the planetarium’s programs are produced at the Kalamazoo Valley Museum. The process begins with the development of a written script. Images are selected from an extensive collection. New artwork is prepared or ordered as the program visual elements are determined.

A small sound booth and control room make up an audio studio. The narration is digitally recorded, then digitized music and sound effects are added. The planetarium has a licensed library of music clips and sound effects to use in producing shows. There are occasional opportunities for volunteers to offer their vocal talents to show production.

More and more, planetarium programs will incorporate computer generated graphics into their content. The computer images will be created from computer artwork produced in Illustrator and Photoshop, digitized video segments edited in Premiere, and 3D computer graphic models generated with 3DS Max. There will be many opportunities for student interns and volunteers to develop their skills while offering their artistic talents to show production.

The KVM weather station console is inside the planetarium control room.