dipper@utastro.UUCP (Debbie Byrd) (12/05/84)
Early South Pacific sailors developed a unique way of guiding their ships by the stars. More -- right after this. December 5 Navigation by the Stars Even without the use of special instruments for navigation, it's possible to guide a ship at sea by the stars. Beginning several thousand years ago, Polynesian island-dwellers in the South Pacific used what are called "star paths" to find their way between islands hundreds of miles apart. A star path is just the use of a sequence of stars rising up from the east or setting in the west, and marking a particular direction on the horizon -- the direction to another island where the sailor wants to go. The star paths guiding sailors from one island to another used to be well known, though each star path would of course evolve through the year as different stars gradually became visible with the change of seasons. At any moment the star actually guiding the sailor would be low in the sky -- a star at the bottom of the path that has just risen or is about to set. The voyagers steer toward that star, which they know is in the direction of the island they wish to visit. Pretty soon that star has risen too high or has set. Then the next star in the path -- in approximately the same location near the horizon -- is used in its place. In addition to knowing the star paths, the island navigators also had to know ocean currents and drifts, and to correct their courses accordingly. This remarkable skill in navigating by the stars was handed down by word of mouth. Yet it had been in use for over a millenium before the Europeans -- and their instruments -- arrived four hundred years ago. Script by Diana Hadley and Deborah Byrd. (c) Copyright 1983, 1984 McDonald Observatory, University of Texas at Austin
robison@eosp1.UUCP (Tobias D. Robison) (12/14/84)
On primitive pacific navigation:
Much more about star navigation can be found in "East is a big bird"
by Thomas <somebody>. He studied pacific navigators with great care.
(Unfortunately the point of the book is to harness his findings to
support a pernicious sociological conclusion, but nonetheless...)
Navigators in the Carolina Islands have a "universe" that is much
longer in the E-W direction than N-S. Stars in the southern skies have
many more useful navigational guides in the E-W direction than N-S.
Consequently, N-S trips are relatively short, often done in the day,
and rely heavily upon recognition of currents, reefs, fish species,
and other landmarks. The penalty for missing landmarks in the N-S
direction is to fall out of the carolinas, into open pacific sea.
E-W trips, some of several days duration, are guided heavily by the
stars. In some very tricky cases where it is necessary to point the
canoe towards open, unlandmarked sky at night, the navigator imagines
a non-existent island, and guides the boat according to how it lines
up with stars in the E or W sky on the "opposite side" of the
non-existent island. This is an elegant logical construction for
concentrating all of the navigator's intuitive knowledge.
Navigational information for each possible trip is memorized by the
navigators. Some trips consist of many legs, and thus require chains
of memorized steps. The Carolinians never ventured out of their
general piece of the Pacific in the first 40 years of this century,
but it was nonetheless required for all navigators to learn the
memorized steps to get to:
- several mythical homes of deities
- Austrailia and a few other remote places
Carolinian navigators who entered the Australian navy in WW II were
fascinated to discover that the memorized (and essentially unused)
routes to get to Australia and several other remote places were
essentially correct.
- Toby Robison (not Robinson!)
{allegra, decvax!ittvax, fisher, princeton}!eosp1!robison