The eclipse was first sighted at dawn in eastern India near the town of Guahati before moving north and east to Nepal, Burma, Bangladesh, Bhutan and China
• Datablog: every eclipse until the year 2200

Tourists, astronomers and residents across a swath of Asia turned their eyes to the heavens today as the longest eclipse of the 21st century arrived.

Viewing for many was marred by heavy clouds and rain, but the drama of the total eclipse – as darkness swept a narrow path across the continent – was unmistakable.

Jiaxing in Zhejiang province, picked out by China’s National Astronomical Observatory as one of the best spots to view the phenomenon, was drenched by rain after days of fine weather. Forecasters had warned all eight of the selected sites could suffer bad weather.

Thousands of foreign tourists had come to the little-knownn city of 3.5 million inhabitants. They reportedly included a party from India who had feared monsoon rains might obscure their view at home.

Around a thousand gathered in a public square for an official ceremony to mark the occasion. There were cheers when a glimpse of sun briefly broke through the clouds, shortly before the eclipse was due to begin at 8.22.20.

Visitors grabbed their darkened glasses in anticipation, following reminders that viewing with the naked eye could damage their eyesight.

But they would have little chance to use them: shortly afterwards the heavens opened and torrential rain hit the six viewing spots across the city.

Said Jin Qinlong, director of the tourism administration, said it was the most popular event in the city.

Despite the stress of organising it, he added, he felt “a deep calm and peace” as darkness swept across the land.

The phenomenon began at dawn over the western coast of India, passing over Surat, Indore, Bhopal, Varanasi and Patna, Nasa said. It moved east across Nepal, Burma, Bangladesh and Bhutan and then along China’s Yangtze river valley, home to 300 million.

Thick cloud cover over India obscured the sun when the eclipse began but the clouds parted in several cities, minutes before the total eclipse took place at 6.24am.

In neighbouring Bangladesh, people came out in droves.

“It’s a rare moment, I never thought I would see this in my life,” said Abdullah Sayeed, a college student who traveled to Panchagarh town from the capital Dhaka to view it.

He said cars in the town needed to use headlights as “night darkness has fallen suddenly”.

One of the best views, shown live on several television channels, appeared to be in the Indian town of Varanasi, on the banks of the Ganges river, sacred to devout Hindus.

Thousands of Hindus took a dip in keeping with the ancient belief that bathing in the river at Varanasi, especially on special occasions, cleanses one’s sins. The eclipse was seen there for three minutes and 48 seconds.

From there it passed to southern Japan and across the Pacific Ocean, where it would reach its maximum length of six minutes and 29 seconds.

In Jiaxing, the sun began to slip behind the moon at 8.22.20 and reemerged completely 11.00.21, with total eclipse from 9.35.01 to 9.40.57.

According to Nasa, a total eclipse, when the moon passes between the earth and the sun, is only visible from a narrow strip – about 150km wide – of the Earth’s surface at any one time.

Humans have recorded eclipses for thousands of years, but they were often sources of fear rather than fascination. China’s cabinet – the state council – recognised their enduring power when it issued a directive urging local officials to ensure social stability during the event and urged academics and the media to explain the scientific principles behind it lest it caused blind panic.

Historic Chinese documents suggest that they are portents of change.

“There’s a long tradition in China’s past of the natural world and human world being interconnected so developments in one speak to the other,” said Professor Jeffrey Wasserstrom of the University of California.

“From 2,000 years ago or so, the imperial family was interested in any kind of astronomical knowledge that could help predict eclipses. It’s an early version of spin … if you knew in advance the heavens were displeased you could interpret that as being about bad officials who needed to be reprimanded as opposed to the dynasty being imperilled.

“To what extent anyone thinks in those terms now is another matter.”

On a more prosaic note, Chinese authorities in many towns turned on street lights and ordered all police officers to remain on duty, fearing traffic accidents and other problems.

Yan Jun, director of the National Astronomical Observatories, told the official People’s Daily newspaper that the abrupt blackout might inflict dangers on road transport, shipping, air travel and even medical services and other activities. He suggested telecommunications and power transmission might also be affected due to sudden changes in astronomic gravity and light intensity.

In Jiaxing, residents expressed disappointment at the low visibility but tourists appeared to be taking it in their stride. Pupils from Southend boys high school struck up a rousing chorus of their school song and a briefer rendition of It’s Raining Men as they huddled beneath umbrellas in the square.

“Unfortunately, everything’s eclipsed now,” said Dr Mahamarowi Omar, an amateur astronomer who had brought a tour group from Malaysia just to see the phenomenon.

“It’s something so great that humans should experience it. It’s not only science. We are Muslim and after this we will go and pray to God together. He has brought us the beautiful sky and earth and sun.”

There was still no sign of the sun when the rain cleared, but the sky was darkening second by second as the moon swept across its face somewhere behind the clouds. Grumbles and sighs of frustration turned to gasps.

Moments later Jiaxing enjoyed its second dawn of the day. This time, as the sky lightened, glimpses of an upside-down crescent of the sun could be caught through viewing glasses.

“There’s nothing greater than a solar eclipse,” said Sammy Grech, who had travelled all the way from Malta, where he heads the astronomical society.

“Except the rain,” he added thoughtfully.