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From: Alexandre Eremenko (no email)
Date: Thu Oct 14 2004 - 13:58:41 EDT
I have to correct an error in my previous statement
that Columbus did better in Cel Nav than the
B-52 navigator who missed by 300 miles.
I just checked with Adm. Morison (the main expert on Columbus
navigation). This is not so.
In his first voyage, Columbus was taking Polaris
(from Land with a primitive quadrant (NOT to be confused
with Hadley quadrant/octant) and astrolabe,
and obtained latitude of 42 d while his actual latitude
was approx. 21 d.
On Morison's opinion Columbus confused Polaris with another star.
Another time, also in his first voyage, he took Polaris
altitude from his ship and this time the error was only 3 degrees.
That Sun can be also used to find latitude Columbus did not know.
On the other hand, Morison and others who studied the question
conclude that Columbus was a "genius of dead reckoning".
Morison even says that such masters of DR do not exist in our time
(he was writing in 1940-s).
As an example, in his second voyage, Columbus had to reach the point
(Fort Navidad) where he left some people in his first voyage.
He missed by only 10 leagues (apparently less
than 1 degree) on his 1000 leagues crossing.
The only precise instrument he had in his possession was a compass.
The speed of the ship was determined "visually", by looking at the water
turbulence behind the stern:-)
Alex
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