A rare annular solar eclipse will be visible from Sri Lanka tomorrow (26) after nine years, Professor Chandana Jayaratne of the Department of Physics at the Colombo University said.

An annular solar eclipse happens when the moon covers the sun's centre, leaving the sun's visible outer edges to form a “ring of fire” or annulus around the moon.

He said the annular eclipse would be visible for three hours and fifteen minutes from 8.10 a.m. to 11.25 a.m. in the northern parts of the country.

He also warned people not to look at the sun with the naked eye during the eclipse as it would damage the eyes. 

"The partial eclipse can be observed from about 8.10 a.m. for people in Colombo. The maximum partial phase will occur at 9:36 a.m. and then the moon will cover nearly 87.6% of the sun. The eclipse ends up at 11.22 a.m," he said.

The moon's shadow travels over the Earth's surface and blocks out the Sun's light as seen from Earth. Because the Moon orbits the Earth at an angle, approximately five degrees relative to the Earth-Sun plane (ecliptic), the moon crosses the Earth's orbital plane only twice a year.

“These times are called eclipse seasons because they are the only times when eclipses can occur. For an eclipse to take place the moon must be in the correct phase during an eclipse season; for a solar eclipse, it must be a new moon. This condition makes solar eclipses relatively rare,” he said.

The annular phase of this solar eclipse is visible from Saudi Arabia, southern India, Northern parts of Sri Lanka and parts of Indonesia. It will also be visible as a partial eclipse for those who are in Europe, parts of Asia, Southern parts of Sri Lanka and North-West Australia

The next circular eclipse would be visible to Sri Lanka after twelve years which is on May 21 in the year 2031.

He said people who wish to see the sun directly, to use eclipse glasses such as Welder's glasses rated 14 or higher or solar filters. 

“Never use materials such as sunglasses of any kind even if you wear multiple pairs, colour film, medical X-ray film, smoked glass or tinted glass to directly view the sun, floppy disks, telescopes, binoculars or cameras without specialised sun filters as eye protection when viewing the sun,” he warned.

“The sun’s ultra violet (UV) radiation can burn the retinas in the eyes leading to permanent damage or even blindness. This can occur even if your eyes are exposed to direct sunlight for just a few seconds,” he said. (Chaturanga Samarawickrama)