Transcript Captain Cook and the Transit of VenusMay 11, 2012 Gary Little www.GaryLittle.ca James Cook 1728-1779     Entered Royal Navy 1755 Served in North America during Seven Years War with.

Captain Cook
and the
Transit of Venus
1769
May 11, 2012
Gary Little
www.GaryLittle.ca
James Cook 1728-1779


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
Entered Royal Navy 1755
Served in North America
during Seven Years War
with France
Showed skill for surveying
& cartography early on
Charted entrance to
St. Lawrence River
 Invaluable to Wolfe in assault
on Québec City in 1759

Charted Newfoundland in
intricate detail 1763-1767
Newfoundland Masterpiece
Royal Society Takes Notice
Voyage of Science

1768: Royal Society engaged Cook to measure
the Transit of Venus in South Pacific
 Important measurement for determining the
size of the solar system
 Relied on principles of parallax which requires
measurements at widely separated locations
 Edmond Halley had described the math in 1716
 Surveying teams also sent to:
— Hudson Bay (William Wales / Joseph Dymond)
— North Cape (Jeremiah Dixon / William Bayly)
Served on Cook’s 2nd voyage
Trained George Vancouver
Wales Island in B.C. named for him
Halley
Admiralty Takes Notice
Voyage of Exploration

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“[Cook’s] pains and attention [to surveying] are
beyond any description”
— Governor Graves of Newfoundland
Cook’s reputation was such that he was summoned to
meet with the Earl of Egmont, First Lord of the Admiralty
 “It was virtually unheard of for a mere ship’s master to
meet with the First Lord” — Historical Atlas of Canada
Earl of Egmont
(John Perceval)
Egmont on Sunshine Coast
named for him (by Capt. Richards)
Admiralty Takes Notice
Voyage of Exploration


Admiralty entrusted Cook with secret orders to be
opened after reaching Tahiti:
 “You are to proceed to the Southward in
order to make discovery of … a Continent
or Land of great extent [that] may be
found.”
The predicted southern continent: “Terra Australis”
Mercator 1587
1st Voyage: Timeline

August 26, 1768: Cook left
England in HMB Endeavour
 94 on board

April 13, 1769: arrived in
Tahiti
 June 3, 1769: day of transit
 Measured by Cook and by
astronomer Charles Green
 Two back-up measurements
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
Afterwards: on to NZ and
eastern coast of Australia
July 11, 1771: return to
England
HMB Endeavour
1st Voyage: Scientists on Board

Charles Green, astronomer
 Assistant to Astronomer Royal

Joseph Banks, naturalist
 Future President of the Royal Society

Daniel Solander, botanist
 Apostle of Linnaeus

Herman Spöring, botanist
 Assistant to Solander
Botany Bay, Australia
named for the discoveries
of these botanists.
Chart of Tahiti by Lieut. J. Cook
Point Venus
Fort Venus
Fort Venus
A Plan of Fort Venus
Astronomical Clock
Observatory
Observing Venus
Mr. Banks shews the Indians
the Planet Venus on the Sun.
Joseph Banks was the
expedition’s naturalist.
“Appearances of Venus”
James Cook
Charles Green
1769 Transit of Venus: Results
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“This day prov’d as favourable to our purpose as we could wish,
not a Clowd was to be seen … and the Air was perfectly clear, so
that we had every advantage we could desire in Observing the
whole of the passage of the Planet Venus over the Suns disk: we
very distinctly saw an Atmosphere or dusky shade round the
body of the Planet which very much disturbed the times of the
contacts particularly the two internal ones.” — Cook
Sabotaged by “black drop effect” in Tahiti and elsewhere
Oxford Professor Thomas Hornsby wrote in Philosophical Transitions
December 1771 that the 1769 measurements indicated that “the mean
distance from the Earth to the Sun is 93,726,900 English miles”
 The radar-based value used today for the astronomical unit is
92,955,000 miles
 This is a difference of only 0.8%
1769 Transit: Commemoration
Cook: One Busy Captain
First voyage:
1768-1771
Second voyage: 1772-1775
Third voyage: 1776-1779
James Cook: 3rd Voyage
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The first European to set
foot on the coast of what is
now British Columbia
Came from south and
landed at Nootka Sound
on the west coast of
Vancouver Island
 March 30, 1778
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
Triggered the fur trading
frenzy that began in 1785
Famously missed Juan de
Fuca Strait en route
“In this very latitude, Geographers have
placed the pretended strait of Juan de
Fuca. But nothing of that kind presented
itself to our view, nor is it probable that
any such thing ever existed.”
James Cook 1778
Nootka
Sound
Friendly Cove
James Cook 1778
B.C. coast is uncharted!
Capt. James Cook, R.I.P.

Cook died on the beach in Hawaii on February 14, 1779
 Less than 10 years after measurement of Transit of Venus
 Less than 1 year after “discovering” British Columbia
OCEANI INVESTIGATOR ACERRIMVS
“The most intrepid investigator of the seas”
Enjoy the Transit
“The fascination with the Transit of
Venus, and the emotional impact of
viewing it, comes from knowing its
history… An entire continent,
Australia, was settled by Europeans as
a result of James Cook’s transit
expedition. Beset by disease and
deprivation, expedition leaders often
gave their lives in pursuit of their
precious transit timings made in
far-off lands.” — Alan Dyer
Transit begins June 5, 2012 @ 3:05:43 pm / Davis Bay
Gary Little Contact Info
[email protected]
604-741-5347
www.GaryLittle.ca