Astro-tec, which currently offers standard lap seam domes as well as ultimate seam domes without horizontal seams, is working on another innovation - the world's largest planetarium dome, at the Nagoya City Science Museum in Japan.

The standard dome is 35m (114ft) in diameter, with 696 panels, 96 ribs, and a total area of around 20,000sq ft (1,860sq m). "That size of dome has never been done before," said Astro-tec sales manager Dale Lewis.

Astro-tec has installed large domes in the past, including a 24m (79ft)-diameter dome at New York's Hayden Planetarium, and is getting ready to install another 23m (75ft) dome at Italy's Rainbow Magic Land in mid-2010.

Lewis says large domes are definitely becoming a trend. "Domes can fall anywhere from 7m (23ft) in diameter to 35m at this point. The bigger science centres and museums, it just seems like everybody wants to go as large as they can. Now that we've done Nagoya, we've gotten a couple of requests for 35m," he says. "You have 3D coming into play now, so I think you're also going to see this trend continue as they start investing more money into these projects."