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 measuring the apparent solar parallax between different points on the surface of the Earth. In a 1716 issue of the "Philosophical Transactions of the Royal Society", Edmund Halley illustrated Gregory's theory more fully and explained further how it could establish the distance between the Earth and the Sun. In his report, Halley suggested places that a full transit should be viewed due to a "cone of visibility." Places he recommended for observing the phenomenon included the Hudson Bay, Norway and the Molucca Islands. The next transits would occur in 1761 and 1769. Halley died in 1742, almost twenty years before