Venus (the black spot) travels across the face of the Sun, as seen from Patna City on Wednesday. Pictures by Sachin

Residents of the state capital woke up early on Wednesday to witness a rare beauty spot on the Sun.

The celestial event — the Transit of Venus — usually happens when Venus passes directly between the Sun and the Earth. On Wednesday morning, the neighbouring planet could be seen as a small black dot moving across the face of the Sun.

Though the transit could be seen from daybreak, experts had advised enthusiasts against staring directly into the sun. So, a large number of people — mostly children and youngsters — turned up at Srikrishna Science Centre for safe viewing of the Transit of Venus as early as 6.30am.

They strained their eyes through special telescopes and glasses to observe the conspicuous black spot of Venus travel across the face of the Sun till 10.30am.

Many enthusiasts expected a spectacular event like a solar or lunar eclipse and were a little disappointed when they spotted only a blemish on the otherwise brilliant star. However, they became more enthusiastic when they learnt that none of them would be alive when the event reoccurred in 2117.

“The Transit of Venus is the rarest celestial spectacle. The solar eclipse — which seems more spectacular — is expected to occur six times in this decade. But the next Venus transit would occur only after 105 years,” said Satish Ranjan, education officer, Srikrishna Science Centre.

The Transit of Venus occurs in pairs, with a difference of eight years between the two sightings. The difference between two pairs is 105.5 or 121.5 years. It was observed the first time by young English astronaut Jeremiah Horrocks in 1639.

“It did not look spectacular to begin with. But I am glad that I came and had this once-in-a-lifetime experience,” said Ishita Mishra, a teenager, who caught a glimpse of the “Sun’s Mole” using a welder’s glass on Wednesday morning.

Clear skies made the viewing easier for Mishra and her fellow enthusiasts. Though there was no crowd at Srikrishna Science Centre, small groups of people kept pouring in. The science centre administration had made various arrangements for safe viewing of the Transit of Venus, including 50 welder’s glass. A live webcast of the event by Mauna Loa Observatory, Hawaii, was also organised in its auditorium.

But no more than 10 people were interested to see the telecast. Most were interested to catch a glimpse of the astronomical event themselves.

Ranjan Kumar, a resident of Kankerbagh, had brought his 10-year-old son to the centre on Wednesday. “My son is always keen to learn about stars and planets. I read on the Internet that the next Transit of Venus would occur in 2117. I had missed the opportunity to see the last Venus transit in 2004. Thus, I did not want to miss out on the opportunity to see it this time,” said the enthusiastic father.

The experts who explained the significance of the event to them made the experience more special for the visitors.

“The Transit of Venus occurs in pairs approximately four times in 243 years,” Satish Ranjan explained to the visitors at Srikrishna Science Centre. He added that the maximum contact of the transit on Wednesday was observed at 7.02am, when the Venus was right at the centre of the Sun.

“At that time, the Venus was the largest in the course of the transit,” he said.

Experts also said the reason for the long gap of time between two Transits of Venus, is caused by the difference between the orbital planes of Earth and Venus. If the Venus and the Earth orbited the Sun in the same plane, then transits would happen frequently. However, the orbit of Venus is inclined to the orbit of Earth by nearly 3.4 degrees. So, when Venus passes between the Sun and the earth every 1.6 years, it is usually a bit above or below the Sun. Thus, it is invisible to people on Earth.