In just a few hours time the longest solar eclipse of the 21st century will begin as the Moon gradually tracks a path across the front of the Sun, sending the worlds most populous nations into a premature twilight.

Thousands of people from Japan, the US and Europe have made their way to China and India to observe the natural phenomenon, which will not be exceeded in length for another 123 years.

Solar eclipse 2009 will make landfall at 6.30am local time (0030 UTC) on the western Indian state of Gujarat before racing across India, blacking out the holy city of Varanasi on the banks of the Ganges, squeezing between the northern and southern tips of Bangladesh and Nepal before engulfing most of Bhutan, traversing the Chinese mainland and slipping back out to sea off Shanghai.

China and India will both experience a total eclipse, while Thailand, parts of Indonesia, Burma and Laos will all experience a partial eclipse.

For people living outside of these areas a number of live video streams have been set up so they can track the Moons shadow.

Thaindian news will present a live feed of the eclipse from Guwahati in eastern India, while a live feed from a University of North Dakota expedition will broadcast a live stream China which is available here (http://sems1.cs.und.edu/~sems/index_Video.php)

Another webcast from China is available here (http://www.atlaspost.com/2009tse), while Grupo Saros will have a live webcast from China here (http://www.saros.org/index.html)

Webcast from Guwahati

Video by surajkala

Atlaspost Webcast

University of North Dakota expedition stream