Dome, Sweet, (Portable) Dome
The Spitz A-4 optical-mechanical projector.
Credit: SETI Institute

Last week, I had the opportunity to attend WAC – Western Alliance Conference – in Fairbanks, Alaska, and connect with many people from my former career as a planetarium director. Yep, I?m an ex-planetarium director. For more than 2 decades, I taught astronomy and presented planetarium shows under the dome for people from K to gray – students, teachers and the public. In the early 1990s I moved to Lawrence Hall of Science for a year, and then on to the SETI Institute where I direct education and outreach today. I have a fond spot in my heart for people who share their love of science under the dome, and enjoyed attending the meeting.

But, like all technology, things have changed radically since the early 1970?s when I got my start as an assistant at the Sierra College Planetarium in Rocklin, CA. Sierra had a "cutting edge" planetarium: the latest Spitz A-4 optical-mechanical projector, dual back-projection screens, built-in student response systems, and a nice sound system. A few years after I began work there, we added six 35 mm slide projectors around the dome that would cross fade images for the hot, new 3-screen "multimedia" experience. Our offerings expanded from astronomy to nature programming that took people on photographic trips to the redwoods, the California coast, and other scenic areas. College astronomy classes, field-trip groups from schools, and the public all used the planetarium.

In 1977, I graduated, so to speak, and became the director of the Independence High School Planetarium in San Jose, CA. It had the latest "cutting edge" planetarium from Spitz: the 512 ATM-2 which offered automation for shows. And, there were at least 12 35 mm slide projectors, special effects projectors, and such to choreograph. I won?t go into the amount of time spent preparing the visuals for each program (via clever photographic masking techniques and tiny paint brushes used under microscopes ? computer animation was not then available) but I?m getting ahead of my story. After a few years, I added video projection and amassed a collection of laser video disks (the size of LP records) that allowed me to integrate motion video into planetarium programming. We flew over Olympus Mons, and down through Valles Marineris. We crashed into icy moons orbiting Uranus, and peered beneath the clouds that cover Venus. I had video projected on about one-fourth of my dome, just in front of all visitors. It was the "cutting edge" in planetarium programming.

All-sky video systems began to appear in the late-70s and early 80s. Instead of using the projected stars as stellar wallpaper behind a multi-media slide show, the "bleeding edge" was multiple video projectors that covered the dome, with blended seams. Planetariums became immersion theaters for space experiences. Planetarium projectors also underwent a radical remodel from optical-mechanical systems that showed the sky as seen from Earth, to computer-based systems that projected the universe from any place you cared to linger. Like Captain Picard on "Star Trek," you could "make it so" and zoom off through space to near and distant stars, leaving behind the classic geocentric view of traditional planetariums. These systems have evolved in parallel with Moore?s law in the computer industry, and today, all-dome, full color, hi-res video paints the sky in planetarium domes. Theaters like the Hayden Planetarium at the Rose Center in New York City build programs based on the data from the latest astronomical research and theoretical modeling. Today, there are more than 300 digital theaters worldwide, with more coming online every day.

At the WAC meeting in Alaska, three portable domes (think: globe-shaped tents held up with air pressure provided by a fan) took one and all on adventures through the solar system, and on out into the galaxy. They also took us on tours of fantasy landscapes, impressionist art, Egyptian tombs, and exotic locations. One young student was heard to remark that "this is what television should be" upon emerging from the dome. Planetariums have become immersion theaters that envelop the viewer in environments from nano-particles to the entire universe. They are exciting places to create visual experiences that carry visitors to otherwise inaccessible places and times.

Although, I am sentimental about the realistic and beautiful skies of traditional optical-mechanical projectors, they are largely historical artifacts. Today, the game is all-sky digital video that provides the "traditional experience" of the Earth?s starry sky, and so much more ? so, take me to Sirius, please. 

Visit the Hayden Planetarium website.