Computers helped achieve engineering feats on this project that would have been impracticable in the past. A computer-aided design (CAD) software program, called The Catia, allowed the architect to develop multiple views of the major structures during the preliminary planning stages, and to experiment with different concepts. In particular, it enabled the steel structure of the 87-ft diameter sphere to be sketched out and built. A tripod of steel legs support a circular truss on which the upper hemisphere rests and from which the lower hemisphere is suspended. The top portion of the sphere houses the 432-seat Space Theater, where images are projected onto a hemispheric screen.

Within the Space Theater (which still carries the Hayden Planetarium name, although it is now part of the Rose Center), visitors sit in high-backed auditorium chairs with headrests and look up to the hemispheric dome. Made of off-white colored, perforated aluminum panels, the dome serves as a scrim. The dome is several feet in from the outer surface of the sphere, and the space between the two surfaces-containing scaffolding and catwalks for maintenance of equipment-has a network of conduit enclosing miles of power and communications cabling.

The Hayden opens its show with an earth-centric look at the Milky Way from a custom-built Zeiss Mark IV Star Projector, which uses fiber-optic lighting to cast perfect images of stars and planets. Each star is composed of a high-intensity white light projected through a fiber-optic cable, "making the stars tinier, brighter, clearer and more realistic," said James Sweitzer, special projects director of the planetarium.

After these images fade, the second imaging system takes visitors on a dazzling journey through a three-dimensional universe. These images, produced by a bank of seven high-definition SEOS Prodas video projectors (modified Barco 812 projectors) mounted around the perimeter of the dome, create a fantastic spectacle that guides the viewer through the Milky Way and the star systems and galaxies beyond our own. Five of the projectors cover the sides of the dome and the other two cover the top. A laser system accents different portions of the show by pointing out various astrological details. Tom Hanks narrates the show.

Producing 7.34 million pixels in combination, the video projectors receive digital data streams from a Silicon Graphics Onyx2 InfiniteReality2 visual workstation. Equivalent in power to those used by NASA or the largest military research laboratories, the Onyx 2 supercomputer stores up to two terabytes (2,000 gigabytes) and can simultaneously process 14 gigabytes of data using its 28 central processors. The entire show is stored digitally on Ciprico disk arrays.

Images representing the Orion nebula come from the Hubble Space Telescope. Scientists made a 3-D model of the nebula, which was developed into a digital imaging format, or "movie," by the San Diego Supercomputer Center. Sweitzer said this is the first time something like this has ever been seen-or done.

Digital graphical information from the supercomputer is transmitted from the fourth floor computer room down to each of the seven TV projectors by a Local Area Network using a fiber-optic cabling system as the media.

Hung behind the dome, or scrim, 40 floodlights serve as work lights, or they can be used for events that might want to light the projection surface from above. Four UV fixtures with dousers are used for a blacklight effect at the end of the show.

The sound system provides directional sounds and subwoofer speakers installed into each seat gives visitors a sense of movement and a sensation of "lift off" at the start of the space journey presentation.

The show lighting, the Zeiss projector, the lasers, the slide projectors and the audio system are all run by a Dataton Trax Smartpax show control system. The Dataton system sends MIDI signals to the Express console to run the show lighting, while Silicon Conductor serves as the interface between the Silicon Graphics computer and the Dataton system. Barjy Bernhardt serves as project manager for sound and animation at the museum.