Morning star-gazers track Venus's place in the Sun

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Thousands of Britons woke up yesterday morning to find the Sun was shining down on them in a manner not previously seen by any living person.

Thousands of Britons woke up yesterday morning to find the Sun was shining down on them in a manner not previously seen by any living person.

For those with the necessary viewing equipment - or access to the internet - a small black blob could be seen making its stately progress across the face of the Sun between 6.19am and 12.23pm. The blob was Venus and it is the first time since 1882 that anyone has been able to witness its solar "transit" as it passed directly between the Earth and the Sun. Yesterday's astronomical event was even rarer than the partial transit that occurred 122 years ago. This time the entire transit of Venus from one side of the Sun to the other could be witnessed from Britain during daytime.

The last time this happened was in 1283, although nobody at the time was in a position to know about it as neither the telescope nor the mathematics of planetary motion had been developed.

For once, Britain was blessed with a near-cloudless sky which brought thousands of people of all ages to places with the equipment to display Venus in the best possible light.

Crowds began to form early in the morning at the Royal Observatory in Greenwich, the spiritual home of British star gazing where the former Astronomer Royal Edmond Halley had reasoned that the transit of Venus could be used to calculate the distance between the Earth and the Sun, and hence the size of the solar system.

His prediction, in 1677, of Venus transits in 1761 and 1769 caused a competitive scramble between England and France and led to the famous expedition to Tahiti of Captain Cook, who went on to discover Australia on his way home.

Jim O'Donnell, one of the professional astronomers on hand at Greenwich to explain yesterday's event to the public, said that the day could not have gone better.

"This has been a very exciting occasion. It's one thing to see events like this in pictures or on TV but quite another to look through a telescope and view it with your own eyes," Dr O'Donnell said.

Hundreds also gathered at the small village of Much Hoole in Lancashire where in 1639 a brilliant young man called Jeremiah Horrocks became the first person to both predict and witness a transit of Venus.

Horrocks, a 20-year-old amateur astronomer, had looked at the earlier calculations of the astronomer Johannes Kepler and spotted something about the movement of the planets that he had missed.

Horrocks realised that there was about to be a transit in a matter of weeks and wrote to William Crabtree, a cloth maker friend in Salford: "I beseech you with all thy strength to attend diligently with a telescope."

Horrocks died just two years later but Allan Chapman, a historian of science at Oxford University, says he deserves to be recognised as the true father of British astronomy.

"Horrocks got it dead right. He predicted the transit. He then went on with Crabtree to draw a number of fundamental facts about the nature of the solar system which would today be classed as Nobel prize-winning discoveries," he said.

Yesterday, Horrocks enthusiasts set up viewing equipment in the gardens of the three-storey Jacobean house where he carried out his historic observation from a first-floor bedroom with a telescope costing half a crown.

Riddhi Gupta, 16, was one of three New Zealand students who won an astronomy competition to visit the place where Horrocks carried out his work. "Today has been absolutely fantastic. It was a bit surreal to be stood here and think this is the spot where Jeremiah Horrocks was when he saw the transit all those years ago," she said.

At the Mullard Space Science Laboratory in Surrey, children were told how the event could help identify Earth-sized planets orbiting distant stars, said an astronomer, Andrew Coates.

By measuring the precise drop in the intensity of light coming from the Sun as a result the transit of Venus, scientists hope to get a better understanding of how similar-sized extrasolar planets may cause a similar drop in light intensity coming from a distant sun.

Unfortunately, some of Dr Coates' equipment that had been sent out to Spain because of worries over the British weather malfunctioned. "I wish we'd kept it at home," he said.