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From: dipper@utastro.UUCP (Debbie Byrd)
Newsgroups: net.astro
Subject: StarDate: December 5 Navigation by the Stars
Message-ID: <874@utastro.UUCP>
Date: Wed, 5-Dec-84 02:00:20 EST
Article-I.D.: utastro.874
Posted: Wed Dec  5 02:00:20 1984
Date-Received: Sat, 8-Dec-84 06:31:55 EST
Organization: UTexas Astronomy Dept., Austin, Texas
Lines: 37

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