The lunatic fringe: Is moonlight the miracle cure?

Late one afternoon this February, I set off from Tucson, Arizona, to spend a night beneath the moon. It was rush hour and I found myself joining the stream of commuters on their way home from this sprawling town, the second largest in the state. Gradually the traffic thinned out until after 30 miles I myself peeled off, beckoned by a sign pointing down a dirt road to the right. Ten minutes later, dust billowing in my wake, I pulled up at my destination, a huge mirror nestling in the Sonoran desert.

The Interstellar Light Collector – to give the contraption its full name – sat half-submerged in a crater. It was dusk now and everything glowed pink so that the Collector, in truth an array of 84 separate mirrors, looked as if it had emerged from the red desert landscape. I'd arrived early and was wandering around the 25-ton, six-storey-high device when a man appeared from a nearby marquee pushing a patio heater on a trolley. He waved at me and headed to the far side of the crater where a trailer customised to house yet another mirror – the size of a large satellite dish – stood.

At this time of year it grows cold the instant the sun goes down and the man with the trolley was already wrapped up against it. When he returned he introduced himself as Mike Cagle, site manager in charge of maintaining the machine. A boyish 50-year-old, he was full of enthusiasm for his job. And by the time the night was over he'd taught me all sorts of new things. How every day the moon rises 50 minutes later than the day before. How the light it emits is 500,000 times weaker than sunlight. How it travels faster and faster the higher up it gets. When I asked how powerful the Collector was, he grinned. "It can concentrate light a million times. At noon, we could set the desert on fire."

Now though, night was approaching and Mike and his assistant were making final preparations. Other people were arriving, congregating in the marquee, out of which new age music wafted. Next to the canapés, Richard Chapin, the man behind the whole idea, greeted newcomers with an almost saintly smile. A local entrepreneur turned amateur scientist, Chapin had dreamt up the Collector when a friend fell ill with cancer. Intrigued by the claims made for full spectrum therapies, he wondered whether moonlight could have therapeutic effects if administered in high doses.

While Chapin didn't complete his brainchild in time to help his friend, it has since become a magnet for believers in alternative therapies, as well as those in search of miracles. The night I visited was what Chapin calls a "Wellness Night". And while some local people were simply there to commune with their crystals, others had made the pilgrimage from as far away as Oklahoma and Colorado, hoping to rid themselves of eczema, thyroid conditions and even cancer.

Later, Chapin and I stood together by the edge of the crater. A soft-spoken man, there was something dreamlike about the way he spoke of his invention. "We don't know ... We can only hope," he told me. To our left the pilgrims were being corralled into the trailer two by two, each pair allotted a few minutes, those with more serious conditions allowed to stay longer. I wandered over only to be stopped from having a look inside by Eric, a volunteer whose job it was to guide the bathers on the final leg of their journey to the moonlight. "The guys in there now are naked," he said. "We've just got to be respectful." A hypnotherapist by day, Eric insisted the Collector had cured his lifelong asthma. "I used to live in DC," he told me in the same hushed tones everyone here used. "And when I moved to Tucson I still suffered. It was only once I started coming here that I got better."

While another couple were receiving their dose Eric began rhapsodising about an experiment conducted by Dr Corinne Davies, a professor at the University of Arizona. "She took two lots of seeds and put one in front of the Collector," he explained. "The seeds that were exposed to the moonlight germinated much more successfully. It was incredible." Later on the phone, I asked Dr Davies, currently on sabbatical writing a book, In the Arms of the Moon: A Lunar Spin on the Evolution Story, about her experiment. "It's cool what he's doing," she said of Chapin's invention. "Everyone should have the chance to realise their dreams. But I don't think my results proved anything. It was just a preliminary test ... Still, I didn't expect anything to happen – but it did."

The possibilities of moonlight excite non-scientists too. Over in the marquee, Fabienne Melchior, a self-proclaimed "hermetic witch", sat behind a table stacked with crystals and gemstones. With her purple dress and jet-black hair she seemed the perfect front woman for Moonlight Infusions, a spin-off company launched by Chapin to sell jewellery energised by the Collector. If the venture was meant to help recoup his $2m investment, it has also – should testimonies on his website be believed – enriched others. "MC", a customer from Tucson, claimed the crystals had not only cured her husband's piles but helped her win $1,600 at a local casino too.

At last it was my turn to marinate in the moonlight. I mounted the steps into the trailer but, more from cold than modesty, decided to keep my clothes on. With 84 mirrors aimed at you, the effect is dazzling. A rectangle of silver against the darkness. I stood there for four, five, six minutes, encircled by the icy light. "Have you had enough?" I heard Eric whisper. I opened my eyes. "Yes," I said. "I think I probably have."