By Daily Mail Reporter
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Next month we will be the last people living today to witness one of the rarest astronomical events: the transit of Venus.
If it’s not cloudy, we need do no more than draw back our curtains on June 6 to see the brightest star of the night transformed into a tiny black dot crossing the face of the sun.
But astronomers in the 18th Century travelled thousands of miles and risked their lives to witness this precious sight.
Spectacle: A pelican and fishermen go about their routine on the Flagler Beach Pier while Venus creeps slowly across the rising sun
They did so because they believed Venus held the key to the most pressing astronomical quest of the age: the size of the solar system.
In 1716, British astronomer Edmond Halley had called upon scientists to unite in a project spanning the entire globe. He predicted that on June 6, 1761, Venus would traverse the burning disc of the sun for about six hours.
If several people at different locations across the globe measured and timed this celestial rendezvous, they could calculate the distance between Earth and sun: the base unit for all distances in the solar system and the holy grail of astronomy.
Visionary: Edmond Halley, a member of The Royal Society, predicted that on June 6, 1761, Venus would traverse the burning disc of the sun for about six hours
The only problem was that transits of Venus only occur in pairs, eight years apart, but with an interval of more than a century before they are seen again. After this year, the next transit is not until December 2117.
When Halley asked his international colleagues to rally, only one transit had ever been observed.
Knowing he would not be alive to orchestrate this global cooperation â€" a fact he lamented ‘even on his deathbed’ while holding a glass of wine â€" all he could do was place his trust in future generations.
His gauntlet was taken up when hundreds of astronomers joined the transit project in the 1760s.
At a time when it took six days to travel from London to Newcastle, dozens of them travelled to remote outposts of the world to observe the phenomenon, laden with clocks, huge telescopes and other instruments.
Many risked their lives. With the Seven Years’ War tearing Europe apart, they were even sent into war zones.
They made for strange adventurers: most of their lives were an endless round of dull routine, spending nights under the open sky or engaging in complex computations.
The scientific world was electrified. The observations were the most ambitious scientific project ever planned, because the astronomers needed to watch the transit simultaneously from both the northern and southern hemispheres.
Venus’s path would be shorter or longer across the sun according to each viewing station. With the help of relatively simple trigonometry, the distance between sun and Earth could be calculated, but only if the astronomers shared their results afterwards.
Rare sight: Five transits of Venus have been recorded -- the last one priot to that in 2004 occurred in 1882
It was to be the first international scientific collaboration, and Europe was gripped in transit fever.
The expeditions were organised by the scientific societies of Europe including the Royal Society in London. They sent Nevil Maskelyne, later Astronomer Royal, to St Helena â€" a lone speck of land in the South Atlantic.
With him he took an assistant, trunks full of instruments and more than 100 gallons of wine and rum.
Charles Mason and Jeremiah Dixon, later famed for the Mason-Dixon Line, left Britain for Sumatra, but within four days they were attacked by a French warship.
The two refused to continue but the Royal Society threatened they would be prosecuted as mutineers ‘with the utmost Severity of Law’ unless they pressed on.
Some astronomers waded waist-deep through icy rivers; others saw their ships wrecked by tropical storms. On the day of the transit, June 6, 1761, about 250 official observers at more than 100 locations pointed their telescopes to the sky.
But instead of swiftly moving across the sun, Venus lingered at the edge for up to a minute, making exact timing impossible.
They had one more chance, on June 3, 1769. Once again astronomers were dispatched across the world. Catherine the Great mounted eight expeditions across the vast Russian empire.
Astronomers from Britain, Austria, Switzerland and Russia travelled to the Arctic, where their brandy froze and clocks stopped.
Stunning: Earth's closest planetary neighbour appeared as a black disc 30 times smaller than the Sun's diameter, slowly moving from left to right over the course of six hours when it last appeared
The British even sent Captain James Cook and the Endeavour into the uncharted emptiness of the South Pacific to follow the transit from Tahiti.
Five astronomers died and many more faced unimaginable hardship. One French scientist travelled thousands of miles, facing bloody battles, dysentery and hurricanes only to be defeated by clouds.
When he returned home after 11 years, he had twice failed to see the transit, his heirs had declared him dead and divided up his estate, and he had lost his job.
It took years to collect the global data, but eventually the distance between Earth and sun was determined within a range of 92,900,000 to 96,900,000 miles â€" very close to today’s figure of 92,960,000 miles.
Impressive, but even more importantly, it was the beginning of international scientific collaboration.
On June 6 this year, the sun will rise just before 5am in Britain, and Venus will begin the show about an hour later.
But don’t look into the sun without proper protection. If you have sharp eyes, get some cheap eclipse shades or for a closer look, use binoculars or a telescope with appropriate solar filters.
But spare a moment for those astronomers who faced enemy attacks, deadly diseases and all kinds of adverse conditions when they united to measure the heavens.
Chasing Venus, by Andrea Wulf, is published by Heinemann, priced £18.99. To order your copy for £15.99 inc pp, call 0843 382 1111 or visit mailshop.co.uk/books.
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"Rare sight: Five transits of Venus have been recorded -- the last one priot to that in 2004 occurred in 1882" ......Pretty Sure's comments were spot on and I see the DM has now changed the caption - but to what? Priot??? Hahaha.
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Additionally, the punctaution is erratic throughout, to say the least. This standard of reporting is becoming all too common in the DM. - Pretty Sure, Online, 13/5/2012 13:20 Oh, the irony.
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oulou, Surrey, 13/5/2012 17:04 , Mick Richards is quite right. He knows his Shakespeare, you don't. - EdinEmbra, Edinburgh, Scotland, 13/5/2012 16:49 For goodness sakes, does it really matter? Are we all supposed to know our Shakespeare now?
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for those who are interested research astrotheology and videos of santos bonacci a great subject matter to read!
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Although very interesting, freaks me right out my tights!
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Never look directly at the sun through a telescope. And there is no point using the tacky cardboard eclipse specs either - you won't see anything. It is only a little black dot against the sun. Easily mistaken for or muddled up with a sunspot. Last time we tied a bit of white paper to a chair, then moved our telescope (£50 in local supermarket - you don't need expensive kit) until we could see the image of the sun on the paper on the chair and watched that and took pictures of that. They came out very well. You have to get up early again this time. And we only get the last little bit in Britain, not the whole transit like last time. But if you didn't see it last time worth trying this time, unless of course it is raining.
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EdinEmbra, Edinburgh, Scotland, 13/5/2012 17:49+++++++++++++++++++++++++++ I found your reply rather curt ........... I was only querying whether it was "hoist" or "hoisted." I have to confess, that as I am now in my sixties, I had forgotten that William Shakespeare used the now proverbial phrase "hoist with his own petard" in Hamlet, but as I understand it, "hoist" is an alternative spelling of "hoisted." Apparently, "hoisted" rather than "hoist" is used much more in the US, so one can also say "hoisted with his own petard," even if Shakespeare coined the original phrase? I worked abroad in a French-speaking country with Americans for many years, which probably explains why I am sometimes confused with English spelling or more colloquial phrases used nowadays. Anyway, I found it to be a really interesting article, even if there were errors in it.
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"On June 6 this year, the sun will rise just before 5am in Britain, and Venus will begin the show about an hour later." It will actually be finishing the show an hour later. Get your facts right DM
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"Rare sight: Five transits of Venus have been recorded -- the last occurred in 1882".... s'funny, I could have sworn I observed it on 8 June 2004...
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On June 6 this year, the sun will rise just before 5am in Britain, and Venus will BEGIN the show about an hour later....... Where you you get this rubbish???? The transit starts at about 11pm (BST) on June 5th, well after the sun has set. When the sun rises on the 6th, the transit will be at third contact (edge of Venus at edge of Sun). Fourth contact (end of transit) is at 05:54. Get up at 6 and it will all be over. The only place on Earth when the whole transit could be seen is the western side of the Pacific.
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