Proof of Concept: Il Heliostat di Viganella

The idea to use a large heliostat to deliver winter sunlight to a small village deep in a valley of the Italian Alps, was a success:

The mirror — 870 meters, or 2,900 feet, above Viganella and measuring 8 meters wide by 5 meters high — is motorized and constantly tracks the sun. Computer software tilts and turns the panels throughout the daylight hours to deflect the rays downward. But from Viganella's main square, bathed in reflected sunlight, all that is visible of the false sun is a bright glare from the slope above.

"At first no one believed it could be possible, but I was certain. I have faith in physics," said Giacomo Bonzani, an architect and sundial designer who came up with the idea of reflecting sunlight onto the square and made the necessary astronomical calculations. The project languished for a few years until funding — about €100,000, or $130,000 — came through last year from private and public sponsors.

The mirror was designed by Emilio Barlocco, an engineer whose company specializes in using reflected sunlight to light the entrances to highway tunnels. He read about Viganella's plight on the front page of the Turin daily La Stampa and offered the village his expertise and services. "Whenever you do something for the first time, you're either a pioneer or stupid," he said. "We hope we're the former."

A concrete plinth was anchored to the rock face of the slope above Viganella to serve as the mirror's base. The mirror panels were flown up by helicopter. The software that tracks the sun's rotation is so sophisticated that the rays can be directed anywhere by the computer, which is in the town hall. "If the church or the bar in the town next door has an event, like a baptism, or a wedding, we can shoot the rays there," Midali said. "It's very versatile."

Computer age brings sun to village in shadow of the Alps [iht via tmn]
Previously: On an Unrealized Art Project