Jeremiah Horrocks

Jeremiah Horrocks , 1618?-1641, English astronomer. He made the first observation of the transit of Venus. His Venus in sole visa, which narrates this experience, was printed by Hevelius in 1662. The transit occurred on Nov. 24, 1639; Horrocks watched the small shadow of the planet move part way across the disk of light on a white screen, where the sun's image was focused through a telescope. Other fragments of his works besides the Venus were edited by John Wallis (1672). Horrocks estimated more correctly than anyone else had yet done the distance of the sun from the earth.

Horrocks, Jeremiah(or Jeremiah Horrox) (c. 1618–1641)English astronomer. He refined J.Kepler's Rudolphine Tables of planetary positions, measured the apparent diameters of the planets, and obtained a value of the solar parallax corresponding to an Earth–Sun distance of about 100 million km. In 1639 he observed a transit of Venus which he had predicted from his refinement of Kepler's tables, measuring the planet's diameter on a projected image. On the basis of Horrocks's lunar theory, J.Flamsteed later constructed tables of the Moon's motion which remained the best available until the mid-18th century.