Jack Linthicum wrote:
> BernardZ wrote:
> > In article <1148071007.406832.152470@i40g2000cwc.googlegroups.com>,
> > jacklinthicum@earthlink.net says...
> > > The Phoenicians, great traders who sailed in the Mediterranean Sea
> > > 700BC, mainly sailed within sight of land but they also used celestial
> > > navigation - they used the positions of heavenly bodies to tell them
> > > where they were situated and in which direction they should travel. By
> > > day they would use the sun, by night, the stars. To use this method an
> > > accurate knowledge of how the sun and stars changed position over the
> > > course of time was needed. Records of Phoenician voyages record the sun
> > > apparently changing positions indicating that they must have explored
> > > the southern hemisphere and the coast of Africa. Celestial navigation
> > > has been widely used by sailors all over the world until the last
> > > century.
> > > http://www.soc.soton.ac.uk/CHD/classroom@sea/general_science/early_nav.html
> > >
> > >
> >
> > At that time navigators used dead reckoning.
> >
> > As your article states celestial navigation works in the night time if
> > its not cloudy. The trip to the Americas is a long trip without any land
> > mass to refer too.
> >
> > Okay so how does this Phoenician ship navigate to the required city in
> > the Americas and then back again. Say you miss by 500 kilometers, you
> > may never find the place.
> >
> >
> > --
> > Be careful, what you predict with the theory of human-caused global
> > warming as it will be tested soon enough as we aren't going to reduce
> > carbon dioxide emissions.
> >
> > Observations of Bernard - No 99
>
> At that time navigators used their heads. Poor Pytheas, he went all
> over the British Isles and was at least told of what might be Iceland
> in 300 BC or so and seems to have used celestial navigation. Just
> because the books don't tell you the fact is the navigators navigated.
> Simple rule: if the North Star (or what passes for the North Star, see
> below) is at a certain elevation where you start all point with the
> same elevation will be on the same latitude.
>
> http://www.britannica.com/eb/article-9062076?tocId=9062076
Try and measuring with just your eye the difference of a few degrees
morth or south and that would be a few hundred kilometers difference.
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