page_title: 1769 transit of Venus observed from Tahiti
section_title: Results of the 1769 transit observations
hierarchical_section_title: 1769 transit of Venus observed from Tahiti / Results of the 1769 transit observations
caption_attribution_description: English: Sketchings of the 1769 Venus Transit
context_page_description: On June 3, 1769, British navigator Captain James Cook, British naturalist Joseph Banks, British astronomer Charles Green and Swedish naturalist Daniel Solander recorded the transit of Venus on the island of Tahiti during Cook's first voyage around the world. During a transit, Venus appears as a small black disc travelling across the Sun. This unusual astronomical phenomenon takes place in a pattern that repeats itself every 243 years. It includes two transits that are eight years apart, separated by breaks of 121.5 and 105.5 years. These men, along with a crew of scientists, were commissioned by the Royal Society of London for the primary purpose of viewing the transit of Venus. Not only would their findings help expand scientific knowledge, it would help with navigation by accurately calculating the observer's longitude. At this time, longitude was difficult to determine and not always precise. A "secret" mission that followed the transit included the exploration of the South Pacific to find the legendary Terra Australis Incognita or "unknown land of the South."
context_section_description: The Royal Society was very disappointed in the results of data collected from the transit and Cook's report. The Tahiti observers had trouble with the timing of the stages and their drawings were inconsistent. They later found out that this was also true with the observers at the other locations. Observers from all over noted a haze or "black drop" that seemed to follow Venus making it very difficult to record time entry point on the sun and the exit from the sun.
  For what they believed to be a failure in the observation, The Royal Society decided to blame Green who died on the voyage back to England. Cook's rebuke was so sharp that it was taken from the official proceedings of the Society. Green was not given the opportunity to personally present his own data nor could he defend himself.
caption: Sketchings of the 1769 Venus Transit by Captain James Cook and Charles Green, showing the "black drop effect". Note the differences in the drawings.
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