KOLKATA: If you have a pair of sun goggles, get them dusted for a celestial event on June 6. Venus will crawl across the disc of the sun that day and it can be seen in Kolkata from sunrise till around 10am.
The event has generated tremendous interest across the world since the next transit will occur only in 2117.
As with a solar eclipse, do not look at the sun with naked eyes. “Since Venus will only cover 1/32 of the sun’s disc, looking the event with the naked eye is a strict no-no. You should use scientifically tested aluminized Mylar filter (sometimes called as solar goggles) or No.14 welder’s glass,” said MP Birla Planetarium director (research & academic) Debiprosad Duari.
Using exposed X-ray plates or smoked glass is very dangerous, he warns. “The best method is to project the sun’s image through a telescope or a pinhole camera on a screen or a plane white surface,” he says.
Venus’ transit is an extremely significant event because it was central to the evolution of the first concrete concept of the solar system and ushered in the modern era of astronomical observations for calculating some parameters of the solar system.
Kolkata will miss out the first half of the event as it will happen before sunrise.
“The event is quite rare. Once a transit occurs, it will happen again after a span of eight years. But thereafter a transit will not be seen for 105.5 years. Again after a pair of transits, the next one will happen after a gap of 121.5 years,” explained Duari.
On June 6, the transit will last for about 5 hours 40 minutes. The last part of it will be visible in India. For Kolkata, the transit will start around 3.40am.
The greatest transit – when the black dot of Venus can be seen at the innermost point of the disc of the sun – will occur at 7.02am. The transit will end at around 10.20am. The small disc of Venus will touch the Sun’s disc internally at 10.04am and will be completely out at 10.21am. On June 6, the sun will rise around 4.51am in Kolkata. Though the transit should be seen then onwards, realistically it can only be viewed properly around half hour later.First predicted by Johannes Kepler, the transit of Venus gave proof of Galileo Galilei’s sun-centered model of the solar system.
The entire event of the transit of Venus will be visible from eastern Australia, New Zealand, New Guniea, the Philippines, northern Asia, eastern China, Korea, Japan, the islands of the western Pacific Ocean, Hawaii, Russia, Alaska and north-west Canada. In the far north, the entire transit can also be seen, since the sun will not set. From eastern Canada, United States, the Central America, Caribbean and northwest south America where only the first part of the transit will be visible, before the sun sets down.
However, not all inferior conjunction results in a visible transit. This is because the orbital plane of Venus is inclined at an angle of 3.4 degree to the Earth-Sun orbital plane and Sun, Venus and Earth may not be in a straight line.
Source : http://timesofindia.indiatimes.com/city/kolkata/Miss-this-and-the-next-ones-in-2117/articleshow/13285044.cms