Cook and the Transit of Venus
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The Royal Society's Involvement in Captain Cook's First Voyage and the Observation of the Transit of Venus.
In 1768, Captain James Cook set sail on his first epic voyage aboard the Endeavour. The three-year expedition was to become one of the greatest journeys of European exploration in history, and Cook is now most famous for the contact he and his crew made with the islands of the South Pacific en route. The reason his voyage was commissioned in the first place is less well known. It was in fact a scientific mission, organized by the Royal Society of London.
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Early Astronomy in New Zealand: The South Sea Voyages of James Cook.
Captain Cook's three voyages to NZ brought the first astronomers to this country. Wayne Orchiston has written a short summary of the people, their equipment and their observations. This article scanned courtesy of the Carter Observatory.
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The 1796 Transit of Venus.
Source - The Melbourne Observatory - Australia
Images from Cook's 1769 Observations in Tahiti, the equipment used, maps etc.
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Charles Green (1735 - 1771)
Source - BBC History
Green was born in 1735 in Yorkshire, the son of a farmer. In 1761 he was appointed assistant to the Astronomer Royal at Greenwich. In this capacity he travelled to Barbados in 1763-4 with the astronomer Neville Maskelyn to test a new timekeeping device. The increasing importance of astronomy in nautical navigation required further experiments. Green's astronomical and naval experience helped secure his appointment by the Royal Society as the official astronomer on Cook's expedition to Tahiti to view Venus' transit across the sun. It was hoped that this observation, combined with similar ones worldwide, would establish the distances of each planet from the sun.
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Transits, Travels and Tribulations
Source - By J. Donald Fernie, published on American Scientist website.
The purpose of measuring and timing the passage of Venus across the face of the sun on the very rare occasions it is seen to do this was to establish the scale of the solar system (and eventually the scale of the universe itself).
Observers were sent to very distant parts of the earth because the longer the baseline between them, the more accurate the result, and in the ill-explored world of the 1760s this cost more than one of them his life. We must look at the most famous of them all, the British expedition to the South Pacific for the 1769 transit.
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Astronomical Observations
A transcription of the observations made at King George's Island in the South Sea; by Mr. Charles Green by Appointment of the Royal Society, formerly Assistant of the Royal Observatory at Greenwich, and Lieut. James Cook, of His Majesty's Ship the Endeavour.
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Drawings of the Transit of Venus
Source - The Armagh Observatory
By Captain James Cook and Charles Green, from the Armagh Observatory.
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Cook's and Green's illustrations of the "black drop" effect
Source - The Linda Hall Library - Kansas City - Missouri -USA
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