James Cook’s 1769 transit of Venus expedition at Tahiti

Record summary

James Cook, Charles Green and Daniel Solander observed the 1769 transit of Venus from Tahiti as part of an international effort to measure the astronomical unit. Their journals and scientific reports contain disciplined observations of the sky, instruments, weather and local circumstances. This lead matters because it provides a strong contrast between documented celestial observation and later claims that historical sky reports were UFO encounters. The event is well established, but individual observational discrepancies, atmospheric effects and instrument limitations remain relevant to the history of observation and interpretation.