"thunder" wrote in message
news
On Mon, 12 Mar 2007 11:34:41 -0400, Wilbur Hubbard wrote:

There seems to be a contradiction between 5 and 6. Longitude not
based
on time, yet the need for an accurate timepiece? You seem to
overlook
the obvious, both time, as we measure it, and longitude are based
upon
the same thing, a revolving earth.

No contradiction. Only misconceptions in your mind. Let me explain
one
more time. This time please get your head out of your ass.

1) Astronomers plotted celestial bodies and made tables telling where
these bodies would be in the sky and when.

2) a sextant and tables of celestial body positions can be used to
tell
you your geographical position on the face of the Earth.

3) the TABLES don't work without accurate time because the angles
change
as time changes. A second of time matters. This is because the Earth
rotates.

4) The lat/lon grid system is an arbitrary one. It is based on the
properties of a sphere and has NOTHING to do with time. Time could
stop
but the grid system would remain exactly the same. Picture actual
lines
painted on the Earth's surface. These lines remain even if time
stops.
Time has NOTHING to do with the grid system

5) Time IS USED to reference the exact angle of a celestial body as
it
appears from a given GP on the face of the sphere which GP is defined
by
the lat/lon grid.

Longitude is NOT based upon a revolving Earth. Longitude lines exist
as
an artificial series of lines space on the Earth's surface by
geometric
parameters. Time is not involved one iota. The Earth could stop
rotating
yet the Meridians of Longitude would still exist.

Really? Well, I'm sure you noticed that the longitude lines converge
at
the poles. Let's "arbitrarily" move them, to converge on say Dallas,
think your navigation would work, with or without a timepiece? Don't
think so. The grid is *not* arbitrary, and for all your calculations
to
work, as you admit, you need a reference. That reference is time.


Wrong! Time has nothing to do with it. Boy are some people thick!

Wilbur Hubbard