Alex Filonov wrote:
> bernardz@... wrote:
> > Jack Linthicum wrote:
> > > Jack Linthicum wrote:
> > > > bernardz wrote:
>
> >
> > And three degrees is 300 kilometers. When you box a compass your
> > compass points are 16 Compass Pointers i.e. N,E,S,W; NE,SE,SW,NW;
> > NE,ENE, ESE, SSE, SSW, WSW, WNW, NNW etc.
> >
> > That is 22.5 degrees. say +/- 11.2 degrees.
> >
> > If you double the number of points that is say +/- 5 degrees say 500
> > kilometers. Enough to miss an Island completely.
>
> Compass points have nothing to do with latitude. To measure latitude
> you
> measure elevation angles of stars and planets, Polar star in the
> simplest
> case. Anybody can measure that with their eyes and hands with 3 degree
> accuracy. Add simplest tool, known at least in 1000 BC (a stick
> with several perpendicular sticks), and you can measure Polar star
> elevation
> with 1 degree accuracy. That's max 2 degrees (220 km) latitude error
> (Taking into account the fact that Polar star is not exactly over the
> Pole).
> If you know just a little bit more astronomy, you can probably measure
> latitude with the same instrument with half degree accuracy, that's 55
> km
> distance.
The Greeks called the stars around that quasi north star (Kolchab) the
Phoenician , a name that held until the 19th century. The Phoenicians
used the constellation we call Ursa Minor or the little Dipper because
our current North star---Polaris, Alpha Ursae Minoris--- was 12 degrees
off North at that time. Thales (600 BC) drew the Greeks attention to
the usefulness of the Phoenician.
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