Observers in Orkney and Shetland had the best opportunity to watch the Venue transit of June 2012, but the weather turned out to be too cloudy to see very much.
The Orcadian Sky Notes by John Vetterlein were essential preparation, as they are through the whole astronomical year.
Venus transits occur in pairs, eight years apart, and these pairs are separated by more than a century. The BBC website gives some of the history, describing how the first person to predict a transit of Venus was Johannes Kepler, who was the first person to work out the paths of the planets round the Sun. He died before he could observe the transit of 1631, but the young English astronomer Jeremiah Horrocks watched the next transit, in 1639.
With interest developing, the next transits, of 1761 and 1769, were major scientific events. and it was the potential of observing the 1769 transit from Tahiti that led to Captain Cook‘s first great voyage of exploration aboard his ship the Endeavour.
He was commissioned by the Royal Society, and part of his account of the sighting is quoted in the late Frank Foden’s book Connections: Orkney and Australia. Cook’s Journal of 12 June records:
The day proved as favourable to our purpose as we could wish; not a cloud was to be seen the whole day, and the air was perfectly clear; so that we had every advantage in observing the whole of the passage of the planet Venus over the sun’s disc. We very distinctly saw an atmosphere, or dusky shade, round the body of the planet, which very much disturbed the times of the contact, particularly the two internal ones.”
After the observations, Cook opened sealed orders from the Admiralty instructing him to go further and investigate the possibility of further land in the south Pacific. He first came upon New Zealand, discovered by the Dutch explorer Abel Tasman more than a century before but not yet revisited, and he mapped the coastline. He went on to discover Australia, where he and his men were the first Europeans to land.
They named their place of landfall Botany Bay after the work of the botanists about the Endeavour, but only two days afterwards one of thre crew died and became the first European to be buried in Australia. He was an Orcadian – Forbes Sutherland from Flotta, and the south point of Botany Bay was named after him – Sutherland Point.
A driving force behind Cook’s expedition to observe the transit was the Royal Society’s president, James Douglas, the 14th Earl of Morton, who until 1766 was the owner of the earldom estate in Orkney.
The Earl was a keen astronomer and one of the founders and first president of the institution which became the Royal Society of Edinburgh. He encouraged the British government and King George III to make available the naval ship Endeavour and Cook as commander.
Morton had already been responsible for the initiative that led to the first modern charts of UK waters by the Orcadian Murdoch Mackenzie.
Meanwhile when checking times for any astronomical event, note that astronomers often use Universal Time (UT) which does not have the extra hour that is in the British Summer Time (BST) that our clocks are on at this time of year. And again, remember the safety warnings about the way in which you set up your observations.