Wednesday, February 8, 2012

Great Achievements In Celestial Navigation

Earthrise. NASA photo taken from Apollo 8 by Bill Anders.
Although its actual origins are lost in prehistory, celestial navigation in various forms has played a key role in the spread human beings throughout the world, and even into outer space.

9000 - 8000 BC. Settlers from the mainland of Asia Minor settle the island of Cyprus using the "star path" method of navigation. In star path navigation, a traveler steers on a particular star during certain times, then switched to another as the stars move through the sky.

3000 - 1000 BC. The ancestors of the Polynesians spread out from the Asian mainland using star path navigation. They will eventually spread throughout the South Pacific, arriving in Hawaii between 100 and 300 AD.

150 BC. The Greek astronomer Eratosthenes proves the Earth is round and makes a pretty good guess as to its circumference -- he was off the actual figure by less than three percent. He also saw that the sun's rays are parallel, thus establishing a key concept in celestial navigation: that a heavenly body is directly over a particular spot on the Earth at a particular time, and that this time and position can be predicted.

Using a quadrant, c. 1564
1519 -1522. One ship of the Magellan expedition completes the first known circumnavigation of the world, using a mariner's quadrant and early declination tables as aids to celestial navigation.

1772 - 1775. Captain James Cook's circumnavigation of the world on Resolution is the first to use a modern sextant and the newly-developed Harrison chronometer, used for determining longitude.

1915 - 1916. Using celestial navigation, complicated by heaving Antarctic seas in a a 22-foot boat, the men of Ernest Shackleton's wrecked Endurance expedition make the 800-mile crossing from Elephant Island to South Georgia Island in just twelve days.

1968. While rotating the vessels of the Apollo 8 expedition to take a celestial fix, Lunar Module Pilot Bill Anders takes the famous "Earthrise" photograph.

1970. The troubled Apollo 13 expedition was unable to use star sights to fix its position due to debris from the earlier explosion obstructing the view. Mission commander James Lovell rotated the vehicle to get a sight on the sun instead, using an alternate procedure developed at Mission Control.

Related Posts
Shackleton and South Georgia
Misunderstood Mariners: Enrique de Malacca.
Dad, Magellan, and Greenwich Mean Time


Related Articles
Danny Lee Davis Master's Thesis: Navigation in the Ancient Near Eastern Mediterranean.
University of Pennsylvania Museum of Archaeology and Anthropology: Traditional Navigation in the Western Pacific.
Following The Path Of Discovery: Eratosthenes: The Measurement of the Earth's Circumference.

5 comments:

  1. A correction: Eratosthenes was not technically Greek, but Egyptian. He lived in Alexandria during the reign of pharaoh Ptolemy VI Philometor, whose dynasty was descended from one of Alexander the Great's officers. Members of the dynasty, which lasted from Alexander's death to the beginning of the Roman Empire, always considered themselves Greek, and Egypt during this period is often considered part of the Greek world.

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  2. I believe the "Out of Taiwan" theory is falling out of favor, and the dates for celestial navigation in the eastern Indian Ocean, South China Sea, and western Pacific Ocean are being radically altered. They now appear to reach into the last Ice Age. While it is contentious to say the original colonizers of Australia used celestial navigation, the fact that they crossed no less than 200 km of open water 50,000 - 60,000 years ago hints at such. - Cheers, Heronimus

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