Principle of the Lat/Long system
 

On 1/4/2015 2:11 PM, Gerald Kelleher wrote:
On Sunday, January 4, 2015 10:12:13 AM UTC-8, KC wrote:
On 1/4/2015 11:51 AM, Gerald Kelleher wrote:
On Sunday, January 4, 2015 8:35:33 AM UTC-8, Wayne. B wrote:
On Sun, 4 Jan 2015 07:06:49 -0800 (PST), Gerald Kelleher
wrote:

Having established the original method by which humans came to understand how the appearance of a star defined the Earth's orbital position around the Sun and the number of times it turns within the confines of that orbital circuit using an extra day and rotation over a 4 year period and 4 orbital circuits, the use of the average day and modern timekeeping comes into view. No better person than the great John Harrison to explain the principles -

"The application of a Timekeeper to this discovery is founded upon the
following principles: the earth's surface is divided into 360 equal parts (by imaginary lines drawn from North to South) which are called Degrees of Longitude; and its daily revolution Eastward round its own axis is performed in 24 hours; consequently in that period, each of those imaginary lines or degrees, becomes successively opposite to the Sun (which makes the noon or precise middle of the day at each of those degrees;) and it must follow, that from the time any one of those lines passes the Sun, till the next passes, must be just four minutes, for 24 hours being divided by 360 will give that quantity; so that for every degree of Longitude we sail Westward, it will be noon with us four minutes the later, and for every degree Eastward four minutes the sooner, and so on in proportion for any greater or less quantity. Now, the exact time of the day at the place where we are, can be ascertained by well known and easy observations of the Sun if visible for a few minutes at any
t
ime
from his being ten degrees high until within an hour of noon, or from an hour after noon until he is only 10 degrees high in the afternoon; if therefore, at any time when such observation is made, a Timekeeper tells us at the same moment what o'clock it is at the place we sailed from, our Longitude is
clearly discovered." John Harrison

So here we have the 24 hour day linked to the passage of the Sun across the meridian each day where one rotation and one day always keep in step and especially February 29th which represents the older astronomical achievement that pins the Earth to its orbital position.

The next explanation is intricate but if readers can follow the principles so far that anchor the 24 hour day to rotation there is little that can go wrong understanding the next step which ties the Lat/Long system to the 24 hour AM/PM system.

===

Good grief, we've been dealing with imaginary boats on this group for
years. Now we have to deal with imaginary lines also? I've seen
those lines and they are just as real as Harry's boats.

What you may take for granted in a joking way would have been a serious issue at one stage in history -

http://en.wikipedia.org/wiki/Scilly_...saster_of_1707

The connection between the Lat/Long system along with timekeeping and how it meshes with planetary daily and orbital dynamics has never been explained properly hence this thread.

Anyone with the confidence of a skipper would have no problem so far with the explanation but we are sailing into stormy conceptual waters soon before returning to calmer waters of clear and proper perspectives.


I am guessing most of this is way beyond my pay grade... :)

Absolutely not. The only assumption I make is that people are interested in how the planetary daily and orbital cycles are the basis for timekeeping such as defining the Earth's orbital position in space by the appearance of a single star and the number of times the planet turns within an orbital circuit.

I don't mind the lighthearted poking about imaginary lines however the foundations of navigation using timekeeping developed along a specific path and involves key observations ,some of which were made in antiquity.





I wouldn't worry about it too much. We're probably good for another 100
years or so ....

http://en.wikipedia.org/wiki/Atomic_clock

Principle of the Lat/Long system
 

Gerald Kelleher wrote:
On Sunday, January 4, 2015 10:12:13 AM UTC-8, KC wrote:
On 1/4/2015 11:51 AM, Gerald Kelleher wrote:
On Sunday, January 4, 2015 8:35:33 AM UTC-8, Wayne. B wrote:
On Sun, 4 Jan 2015 07:06:49 -0800 (PST), Gerald Kelleher
wrote:

Having established the original method by which humans came to
understand how the appearance of a star defined the Earth's orbital
position around the Sun and the number of times it turns within the
confines of that orbital circuit using an extra day and rotation over
a 4 year period and 4 orbital circuits, the use of the average day
and modern timekeeping comes into view. No better person than the
great John Harrison to explain the principles -

"The application of a Timekeeper to this discovery is founded upon the
following principles: the earth's surface is divided into 360 equal
parts (by imaginary lines drawn from North to South) which are called
Degrees of Longitude; and its daily revolution Eastward round its own
axis is performed in 24 hours; consequently in that period, each of
those imaginary lines or degrees, becomes successively opposite to
the Sun (which makes the noon or precise middle of the day at each of
those degrees;) and it must follow, that from the time any one of
those lines passes the Sun, till the next passes, must be just four
minutes, for 24 hours being divided by 360 will give that quantity;
so that for every degree of Longitude we sail Westward, it will be
noon with us four minutes the later, and for every degree Eastward
four minutes the sooner, and so on in proportion for any greater or
less quantity. Now, the exact time of the day at the place where we
are, can be ascertained by well known and easy observations of the
Sun if visible for a few minutes at any t
ime
from his being ten degrees high until within an hour of noon, or from
an hour after noon until he is only 10 degrees high in the afternoon;
if therefore, at any time when such observation is made, a Timekeeper
tells us at the same moment what o'clock it is at the place we sailed
from, our Longitude is
clearly discovered." John Harrison

So here we have the 24 hour day linked to the passage of the Sun
across the meridian each day where one rotation and one day always
keep in step and especially February 29th which represents the older
astronomical achievement that pins the Earth to its orbital position.

The next explanation is intricate but if readers can follow the
principles so far that anchor the 24 hour day to rotation there is
little that can go wrong understanding the next step which ties the
Lat/Long system to the 24 hour AM/PM system.

==
Good grief, we've been dealing with imaginary boats on this group for
years. Now we have to deal with imaginary lines also? I've seen
those lines and they are just as real as Harry's boats.

What you may take for granted in a joking way would have been a serious
issue at one stage in history -

http://en.wikipedia.org/wiki/Scilly_...saster_of_1707

The connection between the Lat/Long system along with timekeeping and
how it meshes with planetary daily and orbital dynamics has never been
explained properly hence this thread.

Anyone with the confidence of a skipper would have no problem so far
with the explanation but we are sailing into stormy conceptual waters
soon before returning to calmer waters of clear and proper perspectives.


I am guessing most of this is way beyond my pay grade... :)

Absolutely not. The only assumption I make is that people are interested
in how the planetary daily and orbital cycles are the basis for
timekeeping such as defining the Earth's orbital position in space by the
appearance of a single star and the number of times the planet turns
within an orbital circuit.

I don't mind the lighthearted poking about imaginary lines however the
foundations of navigation using timekeeping developed along a specific
path and involves key observations ,some of which were made in antiquity.

Until there was a dependable shipboard clock, longitude was not really able
to be calculated while at sea.

Principle of the Lat/Long system
 

wrote:
On Sat, 03 Jan 2015 23:27:05 -0600, Califbill
wrote:

wrote:
On Sat, 3 Jan 2015 08:14:26 -0800 (PST),
wrote:

This is the broadest possible overview for those who are unfamiliar with
how the motions of the Earth fit in with human timekeeping and although
it is an injustice to those people who created the system we use today,
the overview is much better than none at all. There is no stopping to
differentiate between the original geocentric astronomers and their
observations from the later heliocentric astronomers who worked off the
idea that the Earth moves between Venus and Mars around the Sun so
readers today don't concern themselves with the level of knowledge of
any given era as this will be taken for granted in order to move the story along.

As the Earth moves through space in its circuit around the Sun,certain
stars lying on or near the same plane as the Earth's orbital motion are
temporarily lost behind the Sun's glare. The older astronomers marked
the passage as the Sun through the constellations (hence birth signs)
but for purposes of this story it is better to consider the apparent
motion of the stars behind the Sun due to the orbital motion of the Earth -

https://www.youtube.com/watch?v=eeQwYrfmvoQ

The anchor for the Lat/Long system originally was based on the
appearance of one particular star as the orbital motion of the Earth
placed the star just far enough to one side of the Sun one morning, That
star was the brightest one in the celestial arena known as Sirius and
can be seen on the bottom left of the image -

https://www.youtube.com/watch?v=eeQwYrfmvoQ

".. on account of the procession of the rising of Sirius by one day in
the course of 4 years,.. therefore it shall be, that the year of 360
days and the 5 days added to their end, so one day shall be from this
day after every 4 years added to the 5 epagomenae before the new year"
Canopus Decree 238 BC

Unbeknownst to themselves, what the Egyptians were actually doing was
defining the Earth's orbital position around the Sun using the seasonal
appearance of a star as a gauge and the number of rotations that fit
inside an orbital circuit, in this case 1461 rotations for 4 orbital
circuits which breaks down into 365 1/4 rotations to one orbital circuit.

This is the founding principle where one 24 hour day keeps in step with
one rotation of the Earth and the basis of the Lat/Long system along
with the reason why the extra day and rotation is introduced in order to
keep the Earth's position in space fixed by the number of rotations,at
least to the nearest rotation.

The next step is the process which equates the 'average' 24 hour day
with 'constant' rotation insofar as the average 24 hour day substitutes
for constant rotation through 360 degrees in that period.






I am reacquainting myself with celestial mechanics as I am playing
with my new sextant.

I inherited an airplane sextant and only tried to play with it once. Has a
disk that a pencil lead marks to get an average of the horizon in a moving
airplane. Is missing the degree wheel I think.

I am reading a book on sextants that talks about a bubble attachment
for aircraft use but they are spendy.
I am going to have to get to the gulf to see a real horizon so I will
be playing with artificial ones here. There are a number of them in
the book, starting with a simple pan of oil.

It is an ANSCO. A-10A

Principle of the Lat/Long system
 

On Sunday, January 4, 2015 12:04:49 PM UTC-8, Califbill wrote:
Gerald Kelleher wrote:
On Sunday, January 4, 2015 10:12:13 AM UTC-8, KC wrote:
On 1/4/2015 11:51 AM, Gerald Kelleher wrote:
On Sunday, January 4, 2015 8:35:33 AM UTC-8, Wayne. B wrote:
On Sun, 4 Jan 2015 07:06:49 -0800 (PST), Gerald Kelleher
wrote:

Having established the original method by which humans came to
understand how the appearance of a star defined the Earth's orbital
position around the Sun and the number of times it turns within the
confines of that orbital circuit using an extra day and rotation over
a 4 year period and 4 orbital circuits, the use of the average day
and modern timekeeping comes into view. No better person than the
great John Harrison to explain the principles -

"The application of a Timekeeper to this discovery is founded upon the
following principles: the earth's surface is divided into 360 equal
parts (by imaginary lines drawn from North to South) which are called
Degrees of Longitude; and its daily revolution Eastward round its own
axis is performed in 24 hours; consequently in that period, each of
those imaginary lines or degrees, becomes successively opposite to
the Sun (which makes the noon or precise middle of the day at each of
those degrees;) and it must follow, that from the time any one of
those lines passes the Sun, till the next passes, must be just four
minutes, for 24 hours being divided by 360 will give that quantity;
so that for every degree of Longitude we sail Westward, it will be
noon with us four minutes the later, and for every degree Eastward
four minutes the sooner, and so on in proportion for any greater or
less quantity. Now, the exact time of the day at the place where we
are, can be ascertained by well known and easy observations of the
Sun if visible for a few minutes at any t
ime
from his being ten degrees high until within an hour of noon, or from
an hour after noon until he is only 10 degrees high in the afternoon;
if therefore, at any time when such observation is made, a Timekeeper
tells us at the same moment what o'clock it is at the place we sailed
from, our Longitude is
clearly discovered." John Harrison

So here we have the 24 hour day linked to the passage of the Sun
across the meridian each day where one rotation and one day always
keep in step and especially February 29th which represents the older
astronomical achievement that pins the Earth to its orbital position.

Principle of the Lat/Long system
 

Gerald Kelleher wrote:
On Sunday, January 4, 2015 12:04:49 PM UTC-8, Califbill wrote:
Gerald Kelleher wrote:
On Sunday, January 4, 2015 10:12:13 AM UTC-8, KC wrote:
On 1/4/2015 11:51 AM, Gerald Kelleher wrote:
On Sunday, January 4, 2015 8:35:33 AM UTC-8, Wayne. B wrote:
On Sun, 4 Jan 2015 07:06:49 -0800 (PST), Gerald Kelleher
wrote:

Having established the original method by which humans came to
understand how the appearance of a star defined the Earth's orbital
position around the Sun and the number of times it turns within the
confines of that orbital circuit using an extra day and rotation over
a 4 year period and 4 orbital circuits, the use of the average day
and modern timekeeping comes into view. No better person than the
great John Harrison to explain the principles -

"The application of a Timekeeper to this discovery is founded upon the
following principles: the earth's surface is divided into 360 equal
parts (by imaginary lines drawn from North to South) which are called
Degrees of Longitude; and its daily revolution Eastward round its own
axis is performed in 24 hours; consequently in that period, each of
those imaginary lines or degrees, becomes successively opposite to
the Sun (which makes the noon or precise middle of the day at each of
those degrees;) and it must follow, that from the time any one of
those lines passes the Sun, till the next passes, must be just four
minutes, for 24 hours being divided by 360 will give that quantity;
so that for every degree of Longitude we sail Westward, it will be
noon with us four minutes the later, and for every degree Eastward
four minutes the sooner, and so on in proportion for any greater or
less quantity. Now, the exact time of the day at the place where we
are, can be ascertained by well known and easy observations of the
Sun if visible for a few minutes at any t
ime
from his being ten degrees high until within an hour of noon, or from
an hour after noon until he is only 10 degrees high in the afternoon;
if therefore, at any time when such observation is made, a Timekeeper
tells us at the same moment what o'clock it is at the place we sailed
from, our Longitude is
clearly discovered." John Harrison

So here we have the 24 hour day linked to the passage of the Sun
across the meridian each day where one rotation and one day always
keep in step and especially February 29th which represents the older
astronomical achievement that pins the Earth to its orbital position.

The next explanation is intricate but if readers can follow the
principles so far that anchor the 24 hour day to rotation there is
little that can go wrong understanding the next step which ties the
Lat/Long system to the 24 hour AM/PM system.

==
Good grief, we've been dealing with imaginary boats on this group for
years. Now we have to deal with imaginary lines also? I've seen
those lines and they are just as real as Harry's boats.

What you may take for granted in a joking way would have been a serious
issue at one stage in history -

http://en.wikipedia.org/wiki/Scilly_...saster_of_1707

The connection between the Lat/Long system along with timekeeping and
how it meshes with planetary daily and orbital dynamics has never been
explained properly hence this thread.

Anyone with the confidence of a skipper would have no problem so far
with the explanation but we are sailing into stormy conceptual waters
soon before returning to calmer waters of clear and proper perspectives.


I am guessing most of this is way beyond my pay grade... :)

Absolutely not. The only assumption I make is that people are interested
in how the planetary daily and orbital cycles are the basis for
timekeeping such as defining the Earth's orbital position in space by the
appearance of a single star and the number of times the planet turns
within an orbital circuit.

I don't mind the lighthearted poking about imaginary lines however the
foundations of navigation using timekeeping developed along a specific
path and involves key observations ,some of which were made in antiquity.

Until there was a dependable shipboard clock, longitude was not really able
to be calculated while at sea.

This is the later part of the story that most hear through the
innovations of John Harrison however these stories only pay minimal
attention to the foundations of timekeeping and where it meshes with the
daily and orbital motions of the Earth.

The idea being that one 24 hour day and one full rotation of the planet
keep in step so that observers can assign significance to February 29th
in terms of the number of times the planet turns inside an orbital
circuit, in this case 1461 rotations across 4 orbital circuits or 365 1/4
rotations to one orbital circuit.

The Lat/Long system is dependent on the daily motion of the Sun crossing
the meridian and this includes the extra day and rotation after four
periods of 365 days. This is important when venturing into errors that
were made in the late 17th century.

Also depends on leap years and leap years without a leap day. And probably
also required a printing press to get the tables distributed widely. All
part of advancement. The Vikings had a compass, which was a secret from
others.

Principle of the Lat/Long system
 

On Sun, 04 Jan 2015 14:07:26 -0500, wrote:

On Sun, 04 Jan 2015 12:54:12 -0500, Wayne.B
wrote:

On Sun, 4 Jan 2015 08:51:32 -0800 (PST), Gerald Kelleher
wrote:

On Sunday, January 4, 2015 8:35:33 AM UTC-8, Wayne. B wrote:
On Sun, 4 Jan 2015 07:06:49 -0800 (PST), Gerald Kelleher
wrote:

Having established the original method by which humans came to understand how the appearance of a star defined the Earth's orbital position around the Sun and the number of times it turns within the confines of that orbital circuit using an extra day and rotation over a 4 year period and 4 orbital circuits, the use of the average day and modern timekeeping comes into view. No better person than the great John Harrison to explain the principles -

"The application of a Timekeeper to this discovery is founded upon the
following principles: the earth's surface is divided into 360 equal parts (by imaginary lines drawn from North to South) which are called Degrees of Longitude; and its daily revolution Eastward round its own axis is performed in 24 hours; consequently in that period, each of those imaginary lines or degrees, becomes successively opposite to the Sun (which makes the noon or precise middle of the day at each of those degrees;) and it must follow, that from the time any one of those lines passes the Sun, till the next passes, must be just four minutes, for 24 hours being divided by 360 will give that quantity; so that for every degree of Longitude we sail Westward, it will be noon with us four minutes the later, and for every degree Eastward four minutes the sooner, and so on in proportion for any greater or less quantity. Now, the exact time of the day at the place where we are, can be ascertained by well known and easy observations of the Sun if visible for a few minutes at any
time
from his being ten degrees high until within an hour of noon, or from an hour after noon until he is only 10 degrees high in the afternoon; if therefore, at any time when such observation is made, a Timekeeper tells us at the same moment what o'clock it is at the place we sailed from, our Longitude is
clearly discovered." John Harrison

So here we have the 24 hour day linked to the passage of the Sun across the meridian each day where one rotation and one day always keep in step and especially February 29th which represents the older astronomical achievement that pins the Earth to its orbital position.

The next explanation is intricate but if readers can follow the principles so far that anchor the 24 hour day to rotation there is little that can go wrong understanding the next step which ties the Lat/Long system to the 24 hour AM/PM system.

===

Good grief, we've been dealing with imaginary boats on this group for
years. Now we have to deal with imaginary lines also? I've seen
those lines and they are just as real as Harry's boats.

What you may take for granted in a joking way would have been a serious issue at one stage in history -

http://en.wikipedia.org/wiki/Scilly_...saster_of_1707

The connection between the Lat/Long system along with timekeeping and how it meshes with planetary daily and orbital dynamics has never been explained properly hence this thread.

Anyone with the confidence of a skipper would have no problem so far with the explanation but we are sailing into stormy conceptual waters soon before returning to calmer waters of clear and proper perspectives.

===

As a self proclaimed expert in these matters, I assume you have also
read "Longtitude" by Daba Sobel and "The American Practical Navigator"
by Nathaniel Bowditch. There is a wealth of information in both.

Bowditch is certainly the gold standard but the 1414 pages of volume 1
and 961 of volume 2 may be a little intimidating.

===

Darn good reading though if you're seriously interested in navigation.
My copies are about 40 years old and almost worn out from being
carried around on my various sailboats over the years.

Principle of the Lat/Long system
 

On Sunday, January 4, 2015 11:45:24 AM UTC-8, Mr. Luddite wrote:
On 1/4/2015 2:11 PM, Gerald Kelleher wrote:
On Sunday, January 4, 2015 10:12:13 AM UTC-8, KC wrote:
On 1/4/2015 11:51 AM, Gerald Kelleher wrote:
On Sunday, January 4, 2015 8:35:33 AM UTC-8, Wayne. B wrote:
On Sun, 4 Jan 2015 07:06:49 -0800 (PST), Gerald Kelleher
wrote:

Having established the original method by which humans came to understand how the appearance of a star defined the Earth's orbital position around the Sun and the number of times it turns within the confines of that orbital circuit using an extra day and rotation over a 4 year period and 4 orbital circuits, the use of the average day and modern timekeeping comes into view. No better person than the great John Harrison to explain the principles -

"The application of a Timekeeper to this discovery is founded upon the
following principles: the earth's surface is divided into 360 equal parts (by imaginary lines drawn from North to South) which are called Degrees of Longitude; and its daily revolution Eastward round its own axis is performed in 24 hours; consequently in that period, each of those imaginary lines or degrees, becomes successively opposite to the Sun (which makes the noon or precise middle of the day at each of those degrees;) and it must follow, that from the time any one of those lines passes the Sun, till the next passes, must be just four minutes, for 24 hours being divided by 360 will give that quantity; so that for every degree of Longitude we sail Westward, it will be noon with us four minutes the later, and for every degree Eastward four minutes the sooner, and so on in proportion for any greater or less quantity. Now, the exact time of the day at the place where we are, can be ascertained by well known and easy observations of the Sun if visible for a few minutes at any
t
ime
from his being ten degrees high until within an hour of noon, or from an hour after noon until he is only 10 degrees high in the afternoon; if therefore, at any time when such observation is made, a Timekeeper tells us at the same moment what o'clock it is at the place we sailed from, our Longitude is
clearly discovered." John Harrison

So here we have the 24 hour day linked to the passage of the Sun across the meridian each day where one rotation and one day always keep in step and especially February 29th which represents the older astronomical achievement that pins the Earth to its orbital position.

The next explanation is intricate but if readers can follow the principles so far that anchor the 24 hour day to rotation there is little that can go wrong understanding the next step which ties the Lat/Long system to the 24 hour AM/PM system.

===

Good grief, we've been dealing with imaginary boats on this group for
years. Now we have to deal with imaginary lines also? I've seen
those lines and they are just as real as Harry's boats.

What you may take for granted in a joking way would have been a serious issue at one stage in history -

http://en.wikipedia.org/wiki/Scilly_...saster_of_1707

The connection between the Lat/Long system along with timekeeping and how it meshes with planetary daily and orbital dynamics has never been explained properly hence this thread.

Anyone with the confidence of a skipper would have no problem so far with the explanation but we are sailing into stormy conceptual waters soon before returning to calmer waters of clear and proper perspectives.


I am guessing most of this is way beyond my pay grade... :)

Absolutely not. The only assumption I make is that people are interested in how the planetary daily and orbital cycles are the basis for timekeeping such as defining the Earth's orbital position in space by the appearance of a single star and the number of times the planet turns within an orbital circuit.

I don't mind the lighthearted poking about imaginary lines however the foundations of navigation using timekeeping developed along a specific path and involves key observations ,some of which were made in antiquity.





I wouldn't worry about it too much. We're probably good for another 100
years or so ....

http://en.wikipedia.org/wiki/Atomic_clock

The issue is not just the Lat/Long system working in tandem with the 24 hour system but also how the original framework was created by defining the Earth's orbital position in space using an annual astronomical event as Sirius comes into view after a period behind the glare of the Sun. The determination is made using the number of rotations hence it takes 4 annual circuits of the Sun to nail down the number of rotations to a close proportion.

To move the narrative on slightly - as one 24 day elapses into the next 24 hours it maintains a relationship to both the daily and orbital features of the Earth. The Lat/Long system is an extension the line-of-sight observation where a star will skip an appearance by one day and one rotation after four periods of 365 days .

The framework where one 24 hour day and one rotation keeps in step is dependent on the original observation which creates the leap day however this is only the beginning of the narrative.

Principle of the Lat/Long system
 

On Sun, 4 Jan 2015 19:18:41 -0800 (PST), Gerald Kelleher
wrote:

I don't mind the lighthearted poking about imaginary lines however the foundations of navigation using timekeeping developed along a specific path and involves key observations ,some of which were made in antiquity.





I wouldn't worry about it too much. We're probably good for another 100
years or so ....

http://en.wikipedia.org/wiki/Atomic_clock

The issue is not just the Lat/Long system working in tandem with the 24 hour system but also how the original framework was created by defining the Earth's orbital position in space using an annual astronomical event as Sirius comes into view after a period behind the glare of the Sun. The determination is made using the number of rotations hence it takes 4 annual circuits of the Sun to nail down the number of rotations to a close proportion.

To move the narrative on slightly - as one 24 day elapses into the next 24 hours it maintains a relationship to both the daily and orbital features of the Earth. The Lat/Long system is an extension the line-of-sight observation where a star will skip an appearance by one day and one rotation after four periods of 365 days .

The framework where one 24 hour day and one rotation keeps in step is dependent on the original observation which creates the leap day however this is only the beginning of the narrative.

===

Gerald, I'm curious to know how you happened to discover our little
group here. Welcome. It's good to see a new and relevant topic of
discussion. I have a great deal of respect and admiration for the
folks who made these observations and conclusions in antiquity. In
those days you could be burned at the stake just for stating that the
earth revolved around the sun instead of vice versa. It sometimes
took courage as well as intellect.

As you probably know, careful observation and recording of solar and
planetary motions ultimately paved the way for Newton's theories, and
modern day physics.

Principle of the Lat/Long system
 

This is great reading especially for the technically challenged like me. With my style of lake boating its more like " hey, let's go that away!"

Keep it coming though. This is all good to know...

Principle of the Lat/Long system
 

On Monday, January 5, 2015 6:09:51 AM UTC-8, Tim wrote:
This is great reading especially for the technically challenged like me. With my style of lake boating its more like " hey, let's go that away!"

Keep it coming though. This is all good to know...

Although the Egyptians knew nothing of daily rotation and the orbital motion of the Earth around the Sun, they realized that they could not base their year on a constant stream of 365 days. The flooding of Nile on which their culture depended coincided closely with the annual appearance of Sirius one morning hence their awareness of the brightest star in the celestial arena for practical reasons and the fact that it skips an appearance by one day after 4 years. In dynamical terms, the additional 24 hours represents the orbital distance the Earth needs to travel to bring Sirius back into view or what now has become the February 29th rotation. We omit 6 hours of orbital motion each non leap year as we gauge our day solely by daily rotation and this accumulates to roughly 24 hours of missing orbital distance at the end of 4 orbital circuits and 4 years.

It isn't really possible to continue with the narrative without an explanation which contains the leap day rotation and what it represents in dynamical terms. Perhaps another could explain it better and I have no objections to this however the facts will remain roughly the same.

The maritime tradition, much like astronomy, is among the most noble and ancient human endeavors in terms of sophistication so that people generally don't think of their ancestors in terms of primitive but rather look for the roots of contemporary traditions in older methods and insights. The rules governing navigation from boats to aircraft are one thing but the timekeeping systems on which navigation is based in something else and this requires some knowledge of the Earth's daily and orbital cycles.