The Venus Transit- 2012

The Venus Transit- 2012

The transit of Venus is one of the rarest predictable astronomical event. And the next transit will occur only in December 2117, which I don’t think anyone reading this article will live to see. So try to see it when it occurs on 5th or 6th of June this year (exact date depends on your location. For people living in India the transit will occur on 6th June in the morning. For exact timings visit this website: http://transitofvenus.nl/wp/where-when/local-transit-times/).

A transit is nothing but solar eclipse in another form. In the “normal” solar eclipse what happens is that the eclipsing body, which is moon, happens to have almost the same angular size as the sun and hence is able to cover the entire sun. However, in case of other planets, Mercury and Venus, though they are much larger than the moon, their angular diameter is very small owing to the distance between them and us. Which means that when they are positioned in between the earth and the sun, they appear as a small dot moving across the sun’s luminous surface, and this is the phenomenon which is called transit. The figure below shows a mosaic of 9 images taken in June, 2004 during the occurrence of last Venus transit visible from earth.

Fig 1. Tuesday June 8, 2004. The planet Venus transit in front of the Sun after more than 121 years from the last Venus transit visible from Earth. The picture show the entire solar disk, the complete transit sequence and an small sunspot group close to the centre of the Sun. (Mosaic of 9 different frame).

As for the transit occurring this year, the good news is that a large part of the world will be able to see it quite easily. Figure 3 marks the area from which the transition will be visible.

For easy reference, it will be visible throughout India and you will be able to see it when the Venus has just started to graze the surface of the sun. The transit will last till 10:22 am which means that you will have plenty of time to observe it. Though, you ought to be careful with that. You must not look directly at the sun at anytime, and the transit is best observed either by using eclipse glasses (do not confuse it with the normal sunglasses) or by projecting an image of the sun on some white surface where you will be able to see a black dot moving (as shown in figure 4). Figure 2 shows the progress of the transition with time (only for India).

Fig 2. Progress of the Venus transit, as seen from Kerala, India.

Fig 3. For Northern Hemisphere locations above latitude ~67° north, all of the transit is visible regardless of the longitude. Northern Canada and all of Alaska will also see the entire event. Residents of Iceland are in a unique wedge-shaped part of the path (Region X in figure). They will see both the start and end of the transit but the Sun will set for a short period around greatest transit. A similarly shaped region exists south of Australia (Region Y in Figure 1), but here, the Sun rises after the transit begins and sets before the event ends.

Fig 4. Venus Transit – Projected

For more details, please visit:

      1.       http://www.sunaeon.com/venustransit/#

      2.       http://www.space.com/15541-venus-transit-sun-2012-guide-infographic.html

      3.       http://www.youtube.com/watch?v=3b7a_zXMnnU&feature=youtu.be

      4.       http://en.wikipedia.org/wiki/Transit_of_Venus,_2012

      5.       http://en.wikipedia.org/wiki/Transit_of_Venus

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Ahmad Ryan