1769 Transit of Venus observed from Tahiti while voyaging to (unsuccessfully) observe the 1761 Transit in Sumatra. Using the solar parallax values obtained from the 1769 transit, Hornsby wrote in "Philosophical Transitions" December 1771 that "the mean distance from the Earth to the Sun (is) 93,726,900 English miles." The radar-based value used today for the astronomical unit is . This is only a difference of eight-tenths of one percent. Considering what these astronomers had to work with, their results were "absolutely remarkable". 1769 Transit of Venus observed from Tahiti On June 3, 1769, British navigator Captain James Cook, British naturalist Joseph Banks, British astronomer Charles Green and
1769 Transit of Venus observed from Tahiti navigator, Samuel Wallis, made the first European contact with Tahiti. Wallis returned from his voyage in time to help the Royal Society decide that it would be an ideal location to observe the Transit of Venus. A big advantage was that Tahiti was one of the few islands in the South Pacific that they knew the longitude and latitude of. The Admiralty was not really interested in particularly where in the South Pacific the observation of the Venus transit would take place. They were more interested in the "secret" mission that would be revealed after the Venus transit observation: the