The new sun worshippers - FT.com Growing numbers of "umbraphiles" are travelling to see solar eclipses, and the next is only weeks away People at the Grand Canyon in Arizona watch an annular eclipse in May this year IN Asian and Australian destinations A solar eclipse starts with the oddest light you have ever seen; a unique grey dusk in the middle of the day. The shadows get sharper and the onlookers grow quieter as the crescent sun dwindles. It takes just over two hours for the moon's first bite of the sun to grow until only a ring of light remains, often supplemented by a bright flash through some valley on the moon's rim. This is the so-called "diamond ring," a moment which romantics have used for marriage proposals. Then, for several minutes, the most beautiful sight in the known universe is yours. The sun's atmosphere, the corona, springs into view as soon as the sun's far brighter surface is blocked off. Twisted into bizarre shapes by the sun's magnetic field, the corona is a ghostly and enthralling white veil, seen in a dark daytime sky against a backdrop of stars and planets. The local birdlife panics at the unexpected night but the human audience reacts too, with quiet gasps or even applause. For a growing band of eclipse tourists, the corona is a drug that cannot be repeated often enough. Happily for their finances, the solar system is laid out so that they can only have the experience at most once in a typical year, the next being on November 14. Celestial geometry dictates that this eclipse will be visible along a track less than 200km wide but more than 14,500km long. The route starts in Australia's Northern Territory, passes through northern Queensland, then heads out over the Pacific Ocean. Thousands of tourists are expected in the city of Cairns, which falls in the eclipse path, with more joining special cruises and even hot air balloon rides. Tour operators report a surge in interest in eclipse viewing, sparked by the "eclipse of the century" in July 2009. It was visible across large parts of India and China and lasted six minutes 39 seconds - the longest eclipse until 2132. It filled every hotel in the Yangtze Delta region, where over 30,000 eclipse watchers based themselves, and brought an extra 7,000 foreign tourists to Shanghai, mostly from the US and Japan. China Daily reported at the time that about 80 special flights were staged to allow passengers to see the eclipse even if clouds threatened: a good move, as it rained in Shanghai. "We're finding this sort of holiday to be hugely popular since the China eclipse, and the trend continued for Easter Island the following year," says Simon Grove, head of product at the tour operator Explore. I think the appeal of astronomical tourism in general has increased in recent years too. Last year's spectacular Northern Lights helped to fuel interest that those well-publicised eclipses had ignited. Part of the joy of this hobby is that the moon's shadow can fall anywhere on the earth's surface. This means eclipse-chasing needs careful planning, but also that eclipse-lovers end up in places they would never visit otherwise, including Easter Island and the Antarctic in the past few years. This year's eclipse will take me to Palm Cove, Queensland; the six others I have witnessed were in locations as diverse as the Greek islands, Siberia, and a tiny power station village in rural China. "A total solar eclipse is a compelling and life-changing sight, so we have huge repeat business," says Aram Kaprielian, owner of Travelquest International in Prescott, Arizona, a specialist astronomical tour operator. Perhaps 40-50 per cent of our clients have been with us before. The "diamond ring" effect, just before a total eclipse For November's eclipse Travelquest will have some 200 clients in Australia and a further 500 on three cruise ships, one off the coast of Australia and others near Fiji and Papua New Guinea. Prices range from $2,000 to $26,000 (for the best cabins on a 20-day voyage from Honolulu to Sydney). Future offerings include both the Arctic and the Antarctic, as well as a Mississippi riverboat for the US coast-to-coast eclipse of 2017. Although eclipse-watchers fly long distances, the growth of the hobby taps into enthusiasm for more natural and uncommercialised forms of tourism. And, for all its celestial drama, an eclipse is also a very human event. Any town along the track is en fête for the biggest tourist event of the year; when totality comes, it prompts an emotional response among viewers. (Top tip: tape up the flash on your camera. If it goes off during the eclipse, your popularity with the rest of the party will plunge.) Aficionados agree that no two eclipses are the same. Jay M Pasachoff, professor of astronomy at Williams College, Massachusetts, has spent decades working out why the corona is at a temperature of more than 1m degrees while the visible surface of the sun, the photosphere, is at a mere 6,000 degrees. In the course of this research he has seen 55 eclipses, 29 of them total, but refuses to name a favourite. As he says: "They are all good and each is interesting in its own way." The corona varies in shape over the 22-year sunspot cycle, while the eclipse might be seen high in the sky, over a seascape or a mountain range, or scraping the horizon at dawn or dusk. Alongside the growth in formal tours, thousands of people find their way to eclipses under their own steam. They aim to get as close as possible to the point of greatest totality and to the centre of the eclipse track, for a longer total eclipse, and seek a spot where the odds of clear weather are at their best. And they are adept at booking accommodation long in advance, at a time when demand is at its peak. Nor do these so-called umbraphiles limit their scope to total eclipses. More frequent are partial eclipses and annular eclipses, which occur when the moon is too far away in its orbit to cover the sun completely, so a ring of the solar surface is left visible and the corona does not appear. These eclipses are spectacular, and people travel long distances to see them, but they cannot compare to the sheer beauty and drama of a total eclipse in a clear sky. Martin Ince is author of "The Rough Guide to the Earth" (Rough Guides) Explore Worldwide Travelquest International Nasa has a website dedicated to eclipses at http://eclipse.gsfc.nasa.gov