Cook and Navigation
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HOW COOK DID IT? CELESTIAL NAVIGATION AND THE TRANSIT OF VENUS
A series of four videos introducing maritime navigation that look at the challenge Captain Cook had in navigating the oceans. How the Transit observations contributed to navigation knowledge; the vital role of 'time' in determining longitude; how early navigators used "dead reckoning to fix their location on the surface of the earth, and how to use a sextant to determine latitude. Presented by Commander David Hedgley, FNI, Royal NZ Navy with the participation of Sea Cadets Kerry Halsey, Omar Hamel, Michael Hill, Jean-Louis Morrison, Jamie Shute, Hannah Williams. Filmed at the NZ National Maritime Museum and on board the historic ship 'Ted Ashby' with the support of the Royal NZ Navy.
 COOK, TRANSITS AND NAVIGATION
The Transit of Venus and the Astronomical Unit, Cook's observations and the Transit of Mercury, what is Latitude and Longitude.
THE PROBLEM OF LONGITUDE
Thinking of the Earth like a clock, the noon (Meridian) passage of the sun, and how knowing time can tell you longitude.
NAVIGATION USING DEAD RECKONING
How Cook used dead reckoning with a compass, how he knew the ship's speed, why he was the "navigator of navigators".
HOW A SEXTANT TELLS SAILORS WHERE THEY ARE
How to use a sextant, taking the noon sight to find latitude and longitude and know where you are.
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Early Charts of the South Pacific
This is a collection of early charts of the South Pacific. Images courtesy of the Alexander Turnbull Library.
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James Cook and the 1769 Transit of Mercury.
The name for Mercury Bay near Whitianga was given to mark the site of Cook's observation of a transit of the planet Mercury. This observation took place in the same year as Cook's Tahiti observations of Venus and Cook's astronomers used highly complex astronomical calculations to determine the Longitude of NZ enabling Cook to place his chart more accurately on the map of the world. Wayne Orchiston's article is scanned courtesy of the Carter Observatory.
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A History of Navigation.
As exploration, trade and conquest became increasingly important throughout the 15th, 16th and 17th centuries, it became more and more necessary to be able to chart your place in the world accurately. Prior to Captain James Cook, most navigators relied on 'dead reckoning'. But Cook was to change all that, and turn navigation into a fine art. See how with this great Flash Animation from the BBC.
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The Pacific before Cook
Despite numerous crossings of the Pacific during the 16th century, the vast majority of that ocean lay unexplored by Europe.On this BBCi website Nigel Rigby examines why it took technological advances and innovative explorers such as Cook to open up the Pacific in this 6 part article.
Entering the Pacific
Early knowledge of the Pacific
How natural conditions restricted European knowledge of the Pacific
The West Pacific
How advances in ship design helped exploration
Find out more
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Abel Tasman.
A concise background to Tasman's first voyage when he became the first European to chart New Zealand and Tasmania. Landfalls to this time (1636) had largely been happenstance though a significantly complete picture of the north and west of the continent of Nova Hollandia (Australia) could be mapped. However, many questions on the geography of the area were opened and much subsequent Pacific exploration would be guided by those questions.
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TWO IMAGES FROM TASMAN IN NEW ZEALAND
Images courtesy of the Alexander Turnbull Library.
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Finding Out the Longitude
Source - J. Donald Fernie on the American Scientist website.
The crisis in sea travel became ever more urgent as world exploration and trading developed, so that a Royal Observatory in Paris in 1667 and another in Greenwich in 1675 were established, largely in the hope that they would lead to an astronomical solution to the longitude problem. Why was longitude determination such a difficult problem compared with finding latitude? A very basic answer is that latitude is measured north or south and so is independent of the earth's east-west rotation, whereas longitude's determination by celestial means is affected by that rotation.
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The Harrison-Maskelyne Affair
Source - J. Donald Fernie on the American Scientist website.
In the early 1700s, European monarchies aspired to power by building world-spanning networks of colonies and commercial ventures. As a result, the merchant fleets and navies that connected and protected these assets were critically important. Eighteenth-century sailors led dangerous lives, not least because they seldom knew their exact location on the open ocean. Although navigators readily determined latitude, or north-south position, by estimating the height of certain stars at their zenith, they could not determine longitude. Several countries offered immense financial rewards for a solution to the problem.
The chronometer and the method of lunar distances each had their proponents and the solution of the longitude problem came down to a bitter battle between two Englishmen - John Harrison, a self-educated machinist who set out to make an accurate clock and Nevil Maskelyne, astronomer and scion of the Church of England, who brought the method of lunar distances to fruition.
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