This Mahalaya, when thousands will throng the Hooghly for tarpan, they better seek the sun?s blessings before it does the disappearing act late in the afternoon.

For, an annular solar eclipse will take place after six years, of which Calcuttans will get only a partial view. The last one was on August 11, 1999.

?The October 3 annular eclipse of the sun will be visible from a narrow region extending from the Iberian Peninsula across the African continent and ending in the southern part of the Indian Ocean,? said Debiprosad Duari, director, research & academics, MP Birla Planetarium.

?A partial or sub-solar eclipse will be seen in places like Europe, western Asia, the Gulf countries, most of Africa and India,? Duari added.

For the city, the eclipse will start at 4.31 pm and the maximum eclipse will be visible at 5.14 pm. The sun sets at 5.20 pm on Monday. ?One needs to go to a place with a view of the western horizon unhindered by tall buildings or trees. A solar filter or projection system is a must while viewing and No. 14 Welder?s glass or an aluminised Mylar film is best recommended,? said Duari.

In case of a total solar eclipse, the size of the moon appears to match the size of the sun. But during an annular eclipse, the moon appears too small to completely cover the sun. A brilliant ring (or annulus) surrounds the moon.