All about Mercury transit as the rare phenomenon begins
The Mercury transit 2016 is all set to occur by 4.40pm in India. Here’s all you need to know about the rare phenomenon:india Updated: May 09, 2016 20:43 IST
Astronomers and casual stargazers witnessed Mercury as a dot on the solar disc --- a rare astronomical phenomenon that occurs only 13 times in a century --- from several parts of the world, including India.
The transit of Mercury was first recorded by French astronomer Pierre Gassendi. He observed it through a telescope in 1631, two decades after the instrument was invented.
German astronomer Johannes Kepler had correctly predicted that transit, but died in 1630 before he could witness the event.
The last Mercury lineup was 10 years ago, and the next will be in 2019, followed by 2032 and 2049.
Here’s all you need to know about the rare phenomenon:
Why does this happen
This phenomenon takes place when the Sun, Mercury and Earth all line up and the smallest recognised planet in the solar system is seen as a small black dot travelling from one limb of the solar disc to the other.
The Mercury appears as a dot on the solar disc because its angular size is very small compared to that of the Sun as seen from the Earth.
Highlights of skywatchers’ year
The Mercury transit occurs 13 or 14 times in a century in May and November. The interval between one November transit and next November transit may be 7, 13 or 33 years whereas the interval between one May transit and the next May transit may be 13 or 33 years, a statement by the ministry of earth sciences said.
This last occurred on November 6, 2006, when just the end of the event was visible from the extreme northeastern parts of India at sunrise.
And in case you miss it on Monday, the next Mercury transit will take place on November 11, 2019. But you will have to travel out of India to observe as it will begin after the sunset time of all places in the country.
Wait for 16 years, and you’ll see the next Mercury transit from India on November 13, 2032.
When and where
The spot on the Sun’s face can be seen from most parts of Asia (except southeastern parts and Japan), Europe, Africa, Greenland, South America, North America, Arctic, North Atlantic Ocean and much of the Pacific Ocean area.
While Delhi can see the Mercury transit for 2 hours 20 minutes from 4.41pm till the sunset at 7.01pm, Kolkata can see it from 4.41pm for 1 hour 26 minutes.
Mumbai will see the Mercury passing over the Sun from 4.41pm for about 2 hours 24 minutes, while in Chennai the event will start at 4.41pm and it can be seen for a duration of about 1 hour 45 minutes.
Elsewhere, hold out your telescopes and special viewing films against the Sun anytime after 4.41pm.
The entire transit, from beginning to end, will be visible from eastern North America, northern South America, the Arctic, Greenland, extreme northwestern Africa, western Europe, and the North Atlantic Ocean.
How to see
The Mercury dot is too small to see without high-powered binoculars or a telescope, and looking directly at the Sun, even with sunglasses, could cause permanent eye damage.
“Safe technique to observe is using filter like aluminised mylar, black polymer or welding glass of shade number 14,” the ministry advisory said.
While using X-rays and blackened glass are often used, experts advise against risking your precious eyes over such ‘jugaads’.
In Delhi, the special solar glasses are available at Rs 20-25 at Gnomon Astrotech, Janakpuri.
Where to see
Delhiites and Mumbaikars can make their way to the Nehru Planetarium to get a clearer view of the Mercury transit 4.40pm onwards.
Another sighting has also been organized at 4pm by Space Foundation at WZ-19, Asalatpur, A-3 Block, Janak Puri, New Delhi.
Others can have the best view from their closest planetarium. Click here for full list
Here’s Nasa’s visualisation of the Mercury transit 2016
(With inputs from agencies)