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Sketchings of the 1769 Venus Transit

James Cook and Charles Green · 1769

Engraved sketches by Cook and Charles Green recording their observations of Venus crossing the Sun at Tahiti in 1769.

Cook made these sketches himself during the 1769 transit of Venus, the stated scientific purpose of his first voyage.

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Engraved plate from Philosophical Transactions Vol. LXI, Tab. XIV, p. 410, titled 'Appearances of Venus by Capt. Cook' (top) and 'Appearances of Venus by Mr. Charles Green' (bottom). Each panel shows a series of numbered figures of Venus as a black disc crossing the Sun's curved edge, with arcs representing the Sun's limb at successive moments of the 1769 transit.
James Cook and Charles Green, Sketchings of the 1769 Venus Transit, 1769. Published in Philosophical Transactions.

About this source

What it is

This engraved plate, published in the Philosophical Transactions, reproduces sketches made by Captain James Cook and the astronomer Charles Green during the 1769 transit of Venus. It shows Venus as a black disc crossing the edge of the Sun at different moments, as observed from Tahiti.

Why it matters

Observing this transit was the official scientific reason given for Cook's first Pacific voyage. Measuring it from different places on Earth helped astronomers calculate the distance from Earth to the Sun. The sketches also record a famous problem the observers faced, where the edge of Venus seemed to blur against the Sun, making exact timing difficult.

Look closer

  • Why would governments fund a long sea voyage just to watch an astronomical event?
  • What differences do you notice between Cook's and Green's sketches, and what might explain them?
  • What does this source suggest about the scientific ambitions behind Cook's voyages, beyond exploration and mapping?

This document is part of the curated material that grounds the AI version of James Cook on Humy.ai — when students ask about related events, the AI can quote it and cite it.

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