SINGAPORE - A loud cheer rose from hundreds of onlookers at the Science Centre in Jurong as the Moon moved to obscure the Sun at 1.24pm on Thursday (Dec 26) and form a "ring of fire", in what has been dubbed the "greatest astronomical event in Singapore".

They were among thousands of people across the island who raised their eyes to the skies to catch the annular solar eclipse.

Many came with young children and elderly parents to the Science Centre, one of several popular gathering spots.

Some brought hats, mats, stools and umbrellas for the wait under the hot sun before the eclipse began at about 11.30am. The phenomenon lasted until about 3.20pm.

Others intent on recording the moment came armed with telescopes on tripod stands to photograph the rare sight.

"It's much better when you see it with your own eyes rather than on television or in photos," said Ms Nurul Huda, 27, who was at the Science Centre to attend her first astronomy event.

An annular solar eclipse occurs when the Moon covers the centre of the Sun, giving the appearance of a fiery ring around it.

The sight in the Singapore sky was visible for the first time in two decades, and will next appear in 2063.

Many like Ms Huda said the wait of about 40 years was too long and they would not know where on earth they would be.

"This may be the first and last time I'm seeing this - it is indeed a once-in-a-lifetime experience for me," said Ms Huda, who is in-between jobs.

About 6,000 solar viewing glasses available at the Science Centre were sold out by 1.15pm. People began queueing for them at about 9am.

Science Centre staff were stationed at 12 telescopes, set up in an open space near the centre's Ecogarden, to help people adjust the settings for "a sight to behold".

Associate Professor Lim Tit Meng, chief executive of Science Centre Singapore, said: "It is a once in a lifetime sight for many and the large turnout at the Science Centre Singapore's viewing events underpins how people are naturally curious about what lies beyond."

He added that the 4,500 turnout was double that of the last astronomy-related event at the centre in July, when a movie screening was held to celebrate the 50th anniversary of the Moon Landing. The event was attended by about 2,500 people.

"Today's phenomenon is a celebration of astronomy made possible by STEM (Science, Technology, Engineering and Maths), which allowed us to know when this rare event would happen," noted Prof Lim.

Starting around 11.30am Singapore time, the eclipse peaked at 1.23pm, where 94 per cent of the Sun was obscured. This left its outer edges visible in a "ring of fire" and produced a shadow that momentarily dimmed the island.

Polytechnic senior lecturer Edwin Tan, 43, was one of many who were at National Junior College (NJC) to catch the eclipse with his family. He was excited that "it would be totally dark for one or two minutes".

Dr Kunwar Bir Singh, who was with his 13-year-old daughter and her friend, said he saw an eclipse when he was very young but Thursday's phenomenon was the first time he got to see an annular solar eclipse properly through a telescope.

"It's a new experience, a once-in-a-lifetime thing," said Dr Singh, 43.

Mrs Ophelia See, a 40-year-old housewife who was with her two daughters aged two and seven, the event was "a good opportunity for (my children) to learn about science".

Mr Alfred Tan, 59, vice-principal of administration at NJC and a solar astronomer with 10 years of experience, was slightly disappointed that clouds had partially obscured the eclipse at one point in the crucial two minutes.

But the most important thing was not about witnessing the eclipse, but providing people the opportunity to learn and spend good quality time with their friends and family.

"This is what motivates me," he said, referring to his overnight stay at the school to set up all the solar telescopes on the school field.

"To see it (the next eclipse), I will have to live to more that 100 years old, and that eclipse will not be as spectacular," he added.

His school's eclipse viewing event was organised with the help of 44 student volunteers from NJC's basketball club.

Readers can share their photos of the eclipse with The Straits Times by using #sgeclipse when posting them on Instagram.