Jeremiah
Horrocks
From Wikipedia, the free encyclopedia.
Jeremiah Horrocks (1617 - 1641), sometimes given as Jeremiah
Horrox, was an English astronomer, born in Hoole, Lancashire,
United Kingdom. His father was a small farmer.
At Cambridge he became familiar with the works of Johannes
Kepler, Tycho Brahe, and others. Horrocks was convinced
that Lansberg's tables were inaccurate when Kepler predicted
that a near-miss of the transit of Venus (when the planet
Venus can be seen from Earth as crossing in front of the
Sun) would occur in 1639. Horrocks believed that the transit
would occur, having made his own observations of Venus for
years.
Horrocks focused the image of the Sun through a telescope
onto a piece of card, where the image could be safely observed.
From his location in Much Hoole, Lancashire, he calculated
that the transit was to begin at approximately 3:00pm on
November 24, 1639. He first observed the tiny black shadow
of Venus on the card at about 3:15pm.
His observations allowed him to make a well-informed guess
as to the size of Venus, as well as to make an estimate
of the distance between the Earth and the Sun. His figure
of 59,000,000 miles was far from the 93,000,000 miles that
it is known to be today but it was a far more accurate figure
than any suggested up to that time.
