Some recent comments by an elderly gentleman subscriber to
alt.sailing.asa got me to thinking. The comments indicated a marked lack
of understanding of celestial navigation. I thought I'd take a minute to
put to rest such misconceptions.

1) A grid was arbitrarily placed upon the surface of the Earth. This
grid consists of Meridians of Longitude and Parallels of Latitude. One
can state one's geographical position(GP) on the face of the earth as an
intersection of this grid system.

2) The angle of various heavenly bodies was calculated with reference to
the Earthly grid system and expressed as angles from a given GP at a
given time.

3) Using a sextant one could accurately calculate the angle to a
heavenly body.

4) The tables show angles along various grid lines at various times.

5) In order to use celestial navigation one must have a sextant, tables
and an accurate time piece.

6) Meridians of longitude are not based upon time any more than
parallels of latitude are based upon time.

I hope this helps.

Wilbur Hubbard

On Sun, 11 Mar 2007 20:30:44 -0400, Wilbur Hubbard wrote:

Some recent comments by an elderly gentleman subscriber to
alt.sailing.asa got me to thinking. The comments indicated a marked lack
of understanding of celestial navigation. I thought I'd take a minute to
put to rest such misconceptions.

1) A grid was arbitrarily placed upon the surface of the Earth. This
grid consists of Meridians of Longitude and Parallels of Latitude. One
can state one's geographical position(GP) on the face of the earth as an
intersection of this grid system.

I'll admit to knowing very little about navigation, but I know enough to
realize the grid was not arbitrary.



2) The angle of various heavenly bodies was calculated with reference to
the Earthly grid system and expressed as angles from a given GP at a
given time.

3) Using a sextant one could accurately calculate the angle to a
heavenly body.

4) The tables show angles along various grid lines at various times.

5) In order to use celestial navigation one must have a sextant, tables
and an accurate time piece.

6) Meridians of longitude are not based upon time any more than
parallels of latitude are based upon time.

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.

I hope this helps.

Wilbur Hubbard

"thunder" wrote in message
news
On Sun, 11 Mar 2007 20:30:44 -0400, Wilbur Hubbard wrote:

Some recent comments by an elderly gentleman subscriber to
alt.sailing.asa got me to thinking. The comments indicated a marked
lack
of understanding of celestial navigation. I thought I'd take a minute
to
put to rest such misconceptions.

1) A grid was arbitrarily placed upon the surface of the Earth. This
grid consists of Meridians of Longitude and Parallels of Latitude.
One
can state one's geographical position(GP) on the face of the earth as
an
intersection of this grid system.

I'll admit to knowing very little about navigation, but I know enough
to
realize the grid was not arbitrary.



2) The angle of various heavenly bodies was calculated with reference
to
the Earthly grid system and expressed as angles from a given GP at a
given time.

3) Using a sextant one could accurately calculate the angle to a
heavenly body.

4) The tables show angles along various grid lines at various times.

5) In order to use celestial navigation one must have a sextant,
tables
and an accurate time piece.

6) Meridians of longitude are not based upon time any more than
parallels of latitude are based upon time.

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.

Wilbur Hubbard

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.

"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

"Scotty" w@u wrote in message
...

"Wilbur Hubbard" wrote in
message ...


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


So you can take a noon sighting at 1800?


Think about what you just wrote. I know you're just being your normal
joker self but think about something for once in your life. Ask yourself
how many miles wide a time zone is at the Equator. Given points on the
same parallel of latitude, local noon in this wide zone differs from one
place (longitude) to another even though everybody's clock is the same.

Local noon is a function of the max height of the sun over a particular
GP. The time of local noon has nothing whatsoever to do with the
Meridians of Longitudes which are fixed imaginary lines on the face of
the Earth. Rather local none tells you your GP as referenced to the
fixed grid of lat/lon.


Wilbur Hubbard

"Wilbur Hubbard" wrote in
message ...


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


So you can take a noon sighting at 1800?

SV

On Sun, 11 Mar 2007 20:30:44 -0400, Wilbur Hubbard wrote
(in article ):

Some recent comments by an elderly gentleman subscriber to
alt.sailing.asa got me to thinking. The comments indicated a marked lack
of understanding of celestial navigation. I thought I'd take a minute to
put to rest such misconceptions.

1) A grid was arbitrarily placed upon the surface of the Earth. This
grid consists of Meridians of Longitude and Parallels of Latitude. One
can state one's geographical position(GP) on the face of the earth as an
intersection of this grid system.

2) The angle of various heavenly bodies was calculated with reference to
the Earthly grid system and expressed as angles from a given GP at a
given time.

3) Using a sextant one could accurately calculate the angle to a
heavenly body.

4) The tables show angles along various grid lines at various times.

5) In order to use celestial navigation one must have a sextant, tables
and an accurate time piece.

6) Meridians of longitude are not based upon time any more than
parallels of latitude are based upon time.

I hope this helps.

Wilbur Hubbard


Short but concise.

--
Mundo, The Captain who is a bully and an ass

* Wilbur Hubbard wrote, On 3/12/2007 11:34 AM:


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.

ok ...


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

you need a bit more than that in general


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.

ok


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.

Absolute nonsense. The choice of the equator was certainly not
arbitrary.

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

complete nonsense.


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.

In other words, the objects appear to move with time? That's deep.


Longitude is NOT based upon a revolving Earth.

Are you actually claiming we would have the same lat/lon system even
if the Earth didn't rotate? You aren't very smart, are you?

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.

Total nonsense. The basic unit of time is the "day" which represents
the Earth's rotation on it's axis. The meridians in affect measure
that rotation. Don't you think its more than a coincidence that the
time zones are defined primarily by longitude?

Wilbur Hubbard, grade school dropout.

I'll take that as a 'no'.

SBV


"Wilbur Hubbard" wrote in

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


So you can take a noon sighting at 1800?


Think about what you just wrote. I know you're just being
your normal
joker self but think about something for once in your
life. Ask yourself
how many miles wide a time zone is at the Equator. Given
points on the
same parallel of latitude, local noon in this wide zone
differs from one
place (longitude) to another even though everybody's clock
is the same.

Local noon is a function of the max height of the sun over
a particular
GP. The time of local noon has nothing whatsoever to do
with the
Meridians of Longitudes which are fixed imaginary lines on
the face of
the Earth. Rather local none tells you your GP as
referenced to the
fixed grid of lat/lon.


Wilbur Hubbard