Celestial event of a lifetime

Neha Mehta

New Delhi, June 3:

The sun would probably be shining as bright as ever on June 8, but the morning of that day would be special as a Venus transit will occur after 122 years. A Venus transit is a very rare event that no one alive today has seen. According to officials of the meteorological department here, the transit will begin at 10.46 am and end at 4.50 pm. It is possible to view transits of only Mercury and Venus from earth. On an average, there are 13 transits of Mercury in each century. Transits of Venus usually occur in pairs, with eight years separating the two events. However, more than a century elapses between each transit pair. The first transit ever observed was of Mercury in 1631 by French astronomer Pierre Gassendi. In 1639, Jeremiah Horrocks and William Crabtree became the first to witness a transit of Venus.

Since the invention of the telescope, only six such events have occurred — in 1631, 1639, 1761, 1769, 1874 and 1882. “Planetary transits are a bit like annual eclipses except that the coverage of the sun’s surface is even smaller in this case,” said N Rathnasree, director of the Nehru Planetarium here. “Such a small portion of the sun’s disc is covered by Mercury or Venus when they move in front of the sun that there is no noticeable decrease in the amount of sunlight reaching us.

The greatest transit happens when the centres of Venus and Sun would appear to have the minimum distance as seen from the centre of the earth. “Never try to observe the transit with the naked eye, as doing so may result in the loss of sight forever. “Use solar filters or an indirect projection technique to have a safe view of the transition and eclipses,” Rathnasree said.

The National Science Centre and Nehru Planetarium have organised special events. Nehru Planetarium will conduct a live webcast of the transit on www.gotovega.com. They would also conduct sessions and exhibitions to educate the public about the unusual event. They would also arrange safe methods for the public to have a glimpse of the Venus transit.