Article Posted on : - Jan 14, 2010

A file photo of Annular Solar Eclipse. Stefan Seip Photo.

NEW DELHI (PTI): Astronomy lovers are in for a rare celestial treat as they will be able to witness the century's longest annular solar eclipse on Friday.

"The solar eclipse on January 15 is the longest annular solar eclipse that will occur in the 21st century," Science Popularisation Association of Communicators and Educators (SPACE) C B Devgun told PTI.

A solar eclipse occurs when the Moon passes between the Earth and the Sun, thereby totally or partially obscuring the Earth's view of the Sun, while an annular eclipse occurs when the Moon is farther from the Earth than normal, and hence its apparent size is not quite sufficient to cover the Sun completely, he said.

In annular solar eclipse, the Sun appears as a very bright annulus, which in Latin means 'ring', surrounding the outline of the Moon, giving the appearance of a 'Ring of Fire', Devgun said.

The photosphere of the sun shall be covered by the moon thereby forming a ring of fire in the sky for more than 10 minutes in some parts of India. The path of the annularity in India will pass over the states of Kerala, Tamil Nadu and Mizoram while the partial phase of eclipse will be visible all over the country, he said.

"Apart from India, the annular eclipse will be visible across Africa, the Indian Ocean, Maldives, Sri Lanka, and south-east Asia. The annular phase will begin at 05:13:54 UT (Universal Time) in the Central African Republic and ends on the Chinese Yellow Sea coast at 08:59:01 UT," Indian Institute Of Astrophysics Professor R C Kapoor told PTI.

The time of maximum eclipse is 07:06:31 UT and the annular phase will last over 11 min 08 sec, much longer than a total. This point lies in the Indian Ocean at 1.26N longitude, 68.64E latitude. The duration decreases as we move on the central line east or west of this point. Over Maldives, the full annularity will be for 10.8 min, Kapoor said.

In Delhi, the annular eclipse will start at 11:53 AM and end at 15:11 PM, with a maximum at 1:53 PM.

The north tip of the path of annularity will touch India first at 8.801 N longitude, 76.656 E latitude, about 10 km south of Kollam and about 2 km south west of a nearby place Paravur in Kerala. Vedaranyam in Tamil Nadu will witness the last touch of the annular solar eclipse.

Only properly designed and certified solar filters or goggles should be used to view the annular solar eclipses, Nehru Planetarium Director Rathnasree said.

The safest way to view the Sun's disk is by indirect projection using pinhole cameras, created by projecting an image of the disk onto a white piece of paper or card using a pair of binoculars (with one of the lenses covered), a telescope, or another piece of cardboard with a small hole in it (about 1 mm diameter), he said.