BellaOnline Forums Education Astronomy Transit of Venus - 250th anniversary

On June 8, 2004 there was a celestial event that no one alive had ever observed - a transit of Venus. Only seven of them have been observed in recorded history. If you missed one in 2004 or 2012, sorry to report that the next one isn't due until 2117.

In a transit, Venus is lined up with the Earth and the Sun. It's rather like a lunar eclipse, but Venus is farther away than the Moon, so it doesn't block the Sun. It just appears as a black dot moving slowly across the face of the Sun.

A great international scientific effort took place for the transit of 1761. There was a second attempt for the transit on June 3, 1769 - next week it's the 250th anniversary of this event. Transit of Venus - Measuring the Solar System tells you more about transits and how the observations would provide data to determine the size of the Solar System.

In the north of England in the early 17th century, there was an amazing circle of astronomers. They were well ahead of their time, and included the first two people ever to observe a transit of Venus, Jeremiah Horrocks and his friend William Crabtree. What ended this brief flowering? Peter Aughton tells the story. Unfortunately, there isn't as much to tell as we would wish. Jeremiah Horrocks was in his teens when he was correcting the planetary tables of Johannes Kepler, twenty when he observed the transit of Venus, and twenty-two when he died.

The Transit of Venus - Book Review

The 1769 transit of Venus was a Big Deal. Everyone wanted in on it. Britain's King George III was often referred to as "Farmer George" in England and even less flattering things, of course, in what would become the USA.

But the king was very keen on astronomy, and in order not to miss the transit, had an observatory built near the royal family's summer residence in Kew. It was built on the ruins of an old monastery. But it wasn't just a royal whim, it became a working observatory and the place where official time for the British Parliament was set. (Interestingly, it was also where a murderer was sometimes in attendance when the King walked in the gardens.)

Kew Observatory

How big is the Solar System? 18th century astronomers tried to find out by sending expeditions around the world to measure a transit of Venus. One of these was Captain James Cook's voyage to Tahiti. He went under the auspices of the Royal Society, but he carried secret orders from the British government.

Transit of Venus - Captain Cook 1769

Here's the story of Guillaume Le Gentil who went to India to observe the transit of Venus in 1761 and took eleven years to get home again. War and weather conspired to prevent his making observations and illness further delayed his return. Was he the unluckiest astronomer ever?

Le Gentil - Heroic Failure