New Delhi: In a rare astronomical phenomenon that occurs only 13 times in a century, planet Mercury will be seen as dot on the solar disc from several parts of India on Monday. This phenomenon takes place when the planet will be seen as a small black dot travelling from one limb of the solar disc to the other.
This occurs only when the Sun, Mercury and the Earth are lined up in one plane. It appears as a dot on the disc because its angular size is very small compared to that of the Sun as seen from the Earth.
"The phenomenon is a relatively rare one which occurs 13 or 14 times in a century. It occurs 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.
"In Delhi, the event can be seen for a duration of about 2 hours 20 minutes as it will start at 4.41 PM and sunset will take place at 7.01 PM. Similarly, in Kolkata the event will start at 4.41 PM and it can be seen for a duration of about 1 hour 26 minutes.
"In Mumbai the event will start at 4.41 PM and it can be seen for a duration of about 2 hours 24 minutes, while in Chennai the event will start at 4.41 PM and it can be seen for a duration of about 1 hour 45 minutes," the statement said.
The transit of Mercury will be visible from most parts of of Asia (except south eastern parts and Japan), Europe, Africa, Greenland, South America, North America, Arctic, North Atlantic Ocean and much of the Pacific Ocean area.
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. The last transit of Mercury had occurred on November 6, 2006 when just the end of the event was visible from the extreme north-eastern parts of India at sunrise.
The next transit of Mercury will take place on November 11, 2019 but the event cannot be seen from India as the same will begin after the sunset time of all places in the country. The transit of Mercury on November 13, 2032 will be visible again from India.
"The Sun should never be viewed with the naked eye. Safe technique to observe is using filter like aluminised mylar, black polymer or welding glass of shade number 14," the statement said.