May 2000

Digital Deep Space

Continued from page 1

By Steve Ditlea

But what makes the new Hayden a technological leap forward is its combination of analog and digital technology. While the analog Zeiss system is hardwired to portray specific celestial bodies, the digital projection system displays images and scientific visualizations created by computer. These systems can work together, for instance superimposing a digitally created comet trail against a Zeiss-projected sky. The Digital Dome System here is powered by a Silicon Graphics Onyx2 Infinite Reality workstation, which feeds output to seven projectors. This technology, originally developed for flight simulators in defense applications, creates in the Hayden three-dimensional tours of outer space. Its visual database of billions of stars was compiled by the American Museum of Natural History,with support from the National Aeronautics and Space Administration. Among Hayden II's advances is technology to remove the blurry edges between the projectors' overlapping image-a distraction in previous systems.

The analog and digital projection systems cost about $4 million each, and the Hayden's inaugural show-"Passport to the Universe"-makes extensive use of both."We wanted to see what we could do once we had all the toys," explains James Sweitzer, the planetarium's director of special projects. The show also debuts a scientific triumph: the 3-D mapping of the Orion nebula from Hubble telescope data, allowing a spectacular Star Wars-like fly-through of that distant star grouping. What the digital system gains in flexibility and extensibility, however, it loses in definition; while it makes possible the highest-resolution virtual-reality theater open to the public, its stars pale beside the crispness of the Zeiss optically projected images.

There is a downside to this new technology. Where once the Hayden Planetarium's sky show lasted close to an hour and included informative discussions of constellations and star names, "Passport to the Universe" zips by in a mere 18 minutes. It gives only the briefest glimpse of the constellations. The compressed show enables the planetarium to give twice as many shows per day, compensating for the 200 fewer seats and massive construction costs.An adult ticket price of $19 (including admission to the Natural History museum) puts the outing in the same league as a top ride at Disneyworld (though the lines aren't as bad). Still, this 21st-century planetarium succeeds at what its predecessors have always done best: exposing visitors to the universe's grand scale of space and time, and filling us with awe.