The eclipse was first sighted at dawn in eastern India near the town of Guahati before moving north and east to Nepal, Myanmar, Bangladesh, Bhutan and China

Solar eclipse is seen in Yinchuan, capital of northwest China's Ningxia Hui Autonomous Region, at 8:33 a.m. on Wednesday, July 22, 2009. Photograph: Wang Peng/AP

Tourists, astronomers and residents across a large swathe 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-known city of 3.5m 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 6.24 am.

In neighboring 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 3 minutes and 48 seconds.

From there it passed to southern Japan and across the Pacific Ocean, where it would reach its maximum length of 6 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 150 km 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 Davis.

"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.

本次日食首先是黎明时分在印度东部高哈蒂小镇附近，进而向东部和北部的尼泊尔、缅甸、孟加拉、不丹和中国的方向移动。

中国西北部宁夏回族自治区首府银川拍摄到的日食景象，时值2009年6月22日，星期三上午8点33分。 摄像： 王鹏/美联社

今日，亚洲成千上万的游客、天文学家和当地居民聚集在各地，观看本世纪以来历时最长的一次日食。

乌云和降雨影响了不少地方对日食的观测，但由于亚洲大陆被笼罩在黑暗中便于观景，此次日食的整体观测仍如人所愿。

浙江省嘉兴是中国国家天文观测中心选定的最适宜观景的地点之一，此地在连日放晴的天气后出现降雨。气象台已发出警告，所有被挑选的适宜观看日食的地点都可能天公不作美。

上千名国外游客早早便聚集在这个人口350万的名不见经传的小城市。据悉，其中包括了一个从印度专程前来的团队，因为他们担心自己家乡的季风降雨影响对日食的观测。

大约一千人聚集在广场上举行正式的仪式来纪念此刻。在比预测的日食时间上午8点22分22秒稍早一点的时候，人们看见一丝太阳光从云端中透出，便欢呼起来。

观看者戴上了提前准备的太阳观测眼镜，有关专家提醒，用肉眼直接进行观测会伤害眼睛的视力。

然而他们用得上眼镜的机会不多：在城内6个观测点，天空的乌云散开没多久便下起骤雨。

嘉兴市旅游局局长金琴龙表示，这是本市最为激动人心的一刻。

尽管人员流动疏导管理的压力很大，他补充说，在黑暗笼罩大地的那一刻，他感到一种"平静安宁"的氛围。

日食的景观于黎明时分在印度西岸开始，跨域苏特拉、印多尔、博帕尔、瓦腊纳西和巴特纳，美国宇航局指出，日食景观经过尼泊尔、缅甸、孟加拉和不丹然后沿路降临中国长江流域，该地人口约有3亿。

印度上空乌云密布，在日食出现的时候挡住了太阳；但在个别城市，早晨6点24分，在日食出现的几分钟前乌云便散去。

在邻国孟加拉，人们纷纷跑到户外观看日食。

这是百年难得一见的景观，我从没想到在我有生之年能够看到。" 大学生阿布杜拉·赛义德说道，他从首府达卡赶到盘查噶尔小镇观看奇观。

他说随着"夜晚般的黑暗突然降临",小镇里的汽车必须使用车前灯照明。

在众多最佳观测地点中，印度瓦腊纳西小镇被几家电视台选中，在印度圣河--恒河的岸边进行现场直播。

数千名印度教徒在恒河中沐浴，他们保留着古老的信仰，认为在瓦腊纳西的恒河里沐浴，尤其是在特殊时刻，能够洗清自己的罪恶。日食在当地持续了3分钟48秒。

紧接着日食现象来到了日本南部并跨越太平洋，在那里，日食达到6分29秒的最长持续时间。

在嘉兴，太阳在上午8点22分20秒的时候被月亮挡住，并在11点零21秒的时候完全重现，整个日食时间从9点35分01秒到9点40分57秒。

据美国宇航局所说，整个日食过程，即在月亮位于地球和太阳之间的时间内，也仅仅在地表一条约150公里宽的狭长地带的某一时刻可以观看到。

人类对日食现象的记录可追溯到几千年前，但那时的记录更多的是蒙昧的恐惧，而非理解的热衷。中国国务院意识到了日食的社会影响，并直接指示有关各地当局确保日食期间的社会稳定，并促请专家学者和媒体宣传报道其科学常识，以免出现不必要的恐慌。

中国古代文献里认为日食是变迁的征兆。

美国加州大学戴维斯分校的华志建教授说："中国自古有一个传统观念，那就是自然世界和人类社会的相辅相成。"

"大约两千年前开始，皇室就喜欢通过夜观天象来预测日食出现。这是一个对自然现象的早期的诠释……如果你提前知道了上天的不满，那你可以解释成：当权者昏庸无能受到指责，而政权已岌岌可危。

"而现今抱有这种想法的人已不多。"

中国当局更以一种沉闷的基调指示各地亮起路灯并命令所有警察官员上岗值勤，以免交通事故和其他问题的出现。

中国科学院国家天文台台长严俊告诉官方报纸人民日报记者，日食期间突发的天色变暗可能会引起道路交通、海运和航空的危险，甚至可能影响公共医疗服务或其他活动。他并表示电信服务和电力供应也可能受天文重力和光强度突变的影响。

在嘉兴，当地居民普遍反映对低能见度的失望，但游客们则对此坦然接受。来自英国索森德男子高中的学生们欢呼雀跃合唱起校歌并在广场上撑伞扮演雨人。

"遗憾的是，万物都已寂寥，" 天文爱好者奥马尔先生说道。他率领旅游团从马来西亚来到这里看日食。

"这真是世纪奇景，我们都应该好好享受观赏。这不仅仅是科学现象。我们穆斯林看到这个神奇的景观，要一起向神祈祷。是他带给我们如此瑰丽的天空、大地和太阳的美景。"

当降雨停止的时候，太阳仍未露脸，但当月亮在云层背后挡住太阳时，天空正迅速变暗。正抱怨惋惜着的人们这时发出惊叹。

过一会儿，嘉兴当地又重现破晓。这时，天空渐渐变亮的时候可以通过观测镜看到呈倒立状的太阳的新月形状。

"日食景观真是奇绝无比，"萨米·格列茨说道。他专程从马耳他岛赶来，他是当地天文学界的权威。

"当然，遗憾的是下雨了。"他若有所思地说道。