For us the South Asians, here comes a lifetime chance to watch a rare event in in the solar system called 'Venus Transit', before sunrise on 6 june, 2012. Venus Transit is an alignment of Earth, Venus and the Sun that will not be seen for another 105 years.

The celestial phenomenon known as the Transit of Venus is one of the most eagerly-awaited events in skywatching. In a transit, Venus passes between Earth and the Sun, appearing through the telescope as a tiny black spot that, for some six and a half hours, crawls in a line over the fiery face of the Sun. On the evening of June 5, North America, Central America and the northern part of South America will get to see the start of the transit - clear skies permitting - until those regions go into sunset. All of the transit will be visible in East Asia and the Western Pacific. Europe, the Middle East and South Asia will get to see the end stages of the eclipse as they go into sunrise on June 6.

Only six Transits of Venus have ever been recorded - quite simply because before the phenomenon was predicted by the 17th-century German mathematician Johannes Kepler, no-one knew where to look or had the lenses to do so. For astronomers on 5-6 June, the Transit of Venus offers a chance to gain insights into the planet's notoriously thick, cloudy atmosphere, and use the refraction of sunlight to finetune techniques for hunting planets orbiting distant stars. One of the most useful exercises will be to compare observations of the transit made by Earth-based telescopes, orbital telescopes and robot probes, including Europe's Venus Express.