At 4.40 p.m. on May 9, Delhi will be able to see until sunset, an astronomical phenomenon that takes place approximately 13 times in a century.
Mercury will come exactly in between the Sun and the Earth, and will be seen as a small dark spot moving across the face of the Sun. The phenomenon can be witnessed across the country until the local time of sunset and will last nearly five hours. In New Delhi, the transit will begin at 4.43 p.m. and will last till 6.48 p.m. 19 degrees North of West.
Since Mercury is tiny, a telescope will be required to observe the transit. People are advised not to look at the Sun directly or through any optics, as they may risk permanent blindness. The safest way to view it is by projecting the image of the Sun onto a sheet of paper and looking at that image. Seeing the Sun and the transit of Mercury by projecting its image on a sheet is perfectly safe, says the Astronomical Society of India.
The Society said one need to ensure that the projected image of the Sun is not too small. It should at least be about 15 cm in diameter so that Mercury is visible on the projected image at the time of the transit.
The Society has collaborated with other organisations to broadcast the transit live on the web from different locations across India. The links to these broadcasts are given on its website, besides detailed instructions on how to view the phenomenon. In addition, Rajya Sabha TV will also show a live telecast of the transit.
On an average, about 13 transits of Mercury take place in a century. The 20th century saw 14 transits and the 21st century too will see 14 transits. However, the 22nd century will see 13 transits. These are global numbers, with a single location on the Earth not necessarily having visible access to all the events.
In contrast, transits of Venus are very rare. There were two events in this century — in June 2004 and June 2012. The next transit of Venus will take place in 2117 and 2125.
Transits of Mercury are, however, not as rare as those of Venus, but not very frequent either. In recent times, the transits of Mercury took place in 2003 and 2006.The next transit on view from India will be in 2032.
In collaboration with the Society and SPACE, the Nehru Planetarium here will conduct a sky watch for viewing the transit on the grounds of the Teen Murti House.
