* Astronomy

Blobrana · L

RE: Transit of Venus, 24 November 1639

Blobrana · L

What did Horrocks really see?

Most of us don't know, but we have been deceived for hundreds of years with regard to Jeremiah Horrocks' observation of the 1639 transit of Venus. Every picture showing the Cytherean silhouette on the solar disk as recorded by Horrocks turns out to be plainly wrong. The source of all error: seventeenth century astronomer Johannes Hevelius.
Horrocks didn't leave us any drawings of what he saw on that fateful day of December 4, 1639.
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Blobrana · L

From his location in Much Hoole, Jeremiah Horrocks calculated that the transit of Venus was to begin at approximately 3:00 pm on 24 November 1639 (Julian calendar, or 4 December in the Gregorian calendar). The weather was cloudy, but he first observed the tiny black shadow of Venus crossing the Sun on the card at about 3:15 pm, and observed for half an hour until sunset. The 1639 transit was also observed by his friend and correspondent, William Crabtree, from his home in Broughton.
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