Event Seven Venus transits have occurred since the invention of the telescope in 1631, 1639, 1761, 1769, 1874 and 1882 and 2004. In this century it will happen for the last time tomorrow

Venus is going on a date with the sun on June 6. It is a rare astronomical event that will happen again only after another 105 years, on December 11, 2117! Professor K. Sathivel, President of Coimbatore Astronomy Club explains how Venus, the second planet from the sun and earth's neighbour, will transit across the solar disc early tomorrow. According to S. Anand, Secretary of the club, it will last for about five hours 40 minutes and will be visible from anywhere in India.

“Venus will be seen as a dot, moving across the sun disc,” says Sakthivel. The celestial wonder begins at 3.45 a.m., reaches a mid position by 7 a.m. and ends by 10.15 a.m. It is a rare planetary alignment, writes professor K. Smiles Mascarenhas of Coimbatore Institute of Technology in his article in the Science Reporter. “Transits of Venus had great importance during the early history of modern astronomy. In fact, it was the only time when astronomers had a chance to determine the value of the Astronomical Unit or AU (the average distance between the sun and the Earth).” Today of course, the AU can be estimated with accuracy using space probes and radar techniques.

Preparing for the date

Amateur Astronomers' clubs are getting ready to catch the spectacle. A. Dakshinamurthy plans to watch it on his five-inch reflector telescope star tracker along with students at the Diamond Jubilee High School in Gobichettipalayam. His Astronomy Association creates awareness on the subject in schools and colleges. “We have seen the craters of moon, the Saturn ring, the Jupiter band and its four satellites (the Galileo satellite), and deep sky objects such as the galaxies, nebula and star clusters,” he says.

V.S. Ananda Kumar from Karuttumedu near Saravanampatti is also ready with his eight inch tube telescope. “Venus is the brightest planet and it will transit the sun for the last time in this century,” he says. Kumar organises sky watching for school children on clear nights. K. Krishnaraj in Mettupalayam will bring out his eight inch and three inch sky watcher telescopes for the event. “We have tied up with the Lions Club to show the spectacle and arouse curiosity amongst people in astronomy,” he says. Amateur interest in astronomy is already on the rise, says D. Murugesh of Skypoint Apparatus that deals in astronomy related equipment and science project kits. “One can own a telescope for sky watching at Rs. 4,000. A hand held one comes at Rs.400 and with it you can see the craters of moon,” he says. Amateur astronomers buy medium sized telescopes that cost around Rs.16, 000

A mention in history

Historical records suggest that the Persian astronomer Avicenna observed the 14 May 1032 Venus transit of the sun. Jeremiah Horrocks (1619-1641), a British amateur astronomer, may have been one of the two people who observed the first recorded transit of Venus in 1639.

Astronomer Johannes Kepler, in the early 1600s, was the first person to figure out the shape and properties of planetary orbits. A pair of Venus transits occurred in 1761 and 1769. Astronomers from across Europe observed these transits, and some travelled to far corners of the world to do so. Captain Cook on his voyage to Tahiti and the South Pacific in 1768-69 is also said to have observed the event.

Things to remember

The Coimbatore Astronomy Club with the Perks Astronomy Club organises a session from 7 a.m. to 10 a.m. on June 6 at Perks School

Transit can be viewed without using a telescope. However protect your eyes with sun-viewing goggles or a welder's glass (N0.14)

Through a telescope the Sun should be viewed either by using a full aperture filter or by projection method

Venus will appear as a tiny dot on the surface of the sun

For guidance, call Mr. Anand at 97904-57568/ Mr. Sakthivel at 98434-2594

Sun goggles are available at Skypoint Apparatus in Coimbatore. Call: 94430-77948

Visit: http://coimbatoreastronomyclub.blogspot.com/

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