Mapping the Earth

Here is a link that should be of interest to you bdhfe

http://www.cromleck-de-rennes.com/images/cassini.jpg

It's the meridian surveyed across France begun 1683. Giovanni Cassini was tasked with this survey by the  Paris Academie des Sciences in order to ascertain the shape of earth .

Cassini himself was not a follower of the Copernican model or Newton's theory of gravity but adhered to the Brahe model. Being the premier scientist/surveyor of the day he was given this task.

The  reasoning for the survey was this.
If the theory of Newtonian gravity was correct then earth would be found to flatten at the poles and bulge at the equator ,i.e degrees of latitude would lengthen northwards along the meridian.
Copernicus adherents viewed the earth as a sphere, the prediction being that all degrees of latitude would be equal along any line of meridian

The survey used plane trigonometry with astronomical methods , Polaris giving the N direction and the rotating stars providing true alignment between N - S as they reached their zenith.

Cassini's survey found that from Perpignan S to Dunkirk N degrees of latitude shortened by around 1/800th Northward. So both Copernican and Newtonian models were incorrect.

His results were checked and no fault found , also backed up by other practical astronomers . Both theories were wrong. The age of "enlightenment" was brought to a halt. Huge controversy ensued .A cover up began .

Must go now but it is worth researching this if you get the time. Will add more later.

TyrannicalSawdustRex wrote:Here is a link that should be of interest to you bdhfe

http://www.cromleck-de-rennes.com/images/cassini.jpg

It's the meridian surveyed across France begun 1683. Giovanni Cassini was tasked with this survey by the  Paris Academie des Sciences in order to ascertain the shape of earth .

Cassini himself was not a follower of the Copernican model or Newton's theory of gravity but adhered to the Brahe model. Being the premier scientist/surveyor of the day he was given this task.

The  reasoning for the survey was this.
If the theory of Newtonian gravity was correct then earth would be found to flatten at the poles and bulge at the equator ,i.e degrees of latitude would lengthen northwards along the meridian.
Copernicus adherents viewed the earth as a sphere, the prediction being that all degrees of latitude would be equal along any line of meridian

The survey used plane trigonometry with astronomical methods , Polaris giving the N direction and the rotating stars providing true alignment between N - S as they reached their zenith.

Cassini's survey found that from Perpignan S to Dunkirk N degrees of latitude shortened by around 1/800th Northward. So both Copernican and Newtonian models were incorrect.

His results were checked and no fault found , also backed up by other practical astronomers . Both theories were wrong. The age of "enlightenment" was brought to a halt. Huge controversy ensued .A cover up began .

Must go now but it is worth researching this if you get the time. Will add more later.

TyrannicalSawdustRex,
Thank you for the very interesting information.
Regarding  the latitude shortening when proceeding North along the Paris meridian,  it  would be  good to know  if Cassini was  using Globe-based methods for calculating latitude  or not.

BDH

bdhfe wrote:
Dip and Refraction and Parallax
These variables come into play as a result of adjusting for distances to stars and altitudes.
There is a good explainer on these here:
http://www.siranah.de/html/sail040h.htm

As these variables are used, based on the belief of a globe earth and large distances to the stars, there is then brought into play a Nautical Almanac, of which I have the gravest suspicions.  I believe the devil is in the details in this, as the Almanac is used to to Adjust what we are actually seeing to what they want us to see.  IMO.

Following up on my comments regarding the Sextant and the variables added to adjust the calculation based on the Globe theory, let me  say that these variables,  for the most  part, are based on Theory and not Experience.  Thus they should be eliminated from the picture if we are to arrive at  a mapping based completely on provable constants and variations.

The Altitude (Dip) variable is used because we  are using the horizon with the Sextant.  This would be a valid variable  to use.  However, the method described in this Subject does not  need the use of an Altitude (Dip) adjustment...  All that is done to accomplish the horizon in the method I proposed is to make the surface across which the sun's shadow is moving.... Level...
Second, the Parallax.....   guess  what theory needs Parallax?  
Third, Refraction....  Again, what theory needs  Refraction?

Perhaps, one can still use  the Sextant to calculate  Lat and Long, keeping  its use in line with the method laid out  in this  Subject.  
All we need to do is remove  the variable for Altitude (Dip).
This can be done by employing the Bubble Sextant, which instrument creates an Artificial Horizon that uses Water, which Water  always seeks its  LEVEL.  Hence, the use of Dip is eliminated.

Bubble Sextant, or Octant described here:
https://en.wikipedia.org/wiki/Bubble_octant

Okay, questions to be answered moving forward if  one is  to use a Sextant:
1.  We need True North to give us Latitude.  How will the Sextant provide us  True North and subsequently Latitude?
2.  Once our Meridian is  found, how does the Sextant give us Longitude?

BDH

Basically, we can all use devices that help to determine the true distances. I have no closer knowledge in surveying, but even without this knowledge I can imagine that it is at least possible to determine approximate values. For example in Australia.
The individual distances of national roads can be checked, even if they are not dead straight.
1. north-south >Darwin - Adelaide
2. west-east >Perth - Sydney
These two lines can be checked by auto-mileage, at least roughly.
The biggest discrepancy between the Gleason map and globe maps is in proportion.
Is Australia as elongated as in Gleason, or does it have the proportions as in the globe maps? That should be possible to find out by auto-mileage + interpolation alone.
To what extent a sextant is infallible here I cannot judge, but the more different methods are used, the more clearly we can see which shape is the real one. In fact, since my occupation with FE, it is the shape of Australia that has struck me most. There it seems to me to be easiest to check the proportions in the Gleason map. What is then still missing is the exact position on longitude and latitude. Or in other words:
Only we can determine the actual form of Australia, and this is still shiftable, as long as we have difficulties with the determination of the absolute position.

Dan-cer wrote:Basically, we can all use devices that help to determine the true distances. I have no closer knowledge in surveying, but even without this knowledge I can imagine that it is at least possible to determine approximate values. For example in Australia.
The individual distances of national roads can be checked, even if they are not dead straight.
1. north-south >Darwin - Adelaide
2. west-east >Perth - Sydney
These two lines can be checked by auto-mileage, at least roughly.

Dan-cer,
I completely agree with you on the use of road distance and any other method that is proved by EXPERIENCE and not theory.

Dan-cer wrote:The biggest discrepancy between the Gleason map and globe maps is in proportion.
Is Australia as elongated as in Gleason, or does it have the proportions as in the globe maps? That should be possible to find out by auto-mileage + interpolation alone.
To what extent a sextant is infallible here I cannot judge, but the more different methods are used, the more clearly we can see which shape is the real one. In fact, since my occupation with FE, it is the shape of Australia that has struck me most. There it seems to me to be easiest to check the proportions in the Gleason map. What is then still missing is the exact position on longitude and latitude. Or in other words:
Only we can determine the actual form of Australia, and this is still shiftable, as long as we have difficulties with the determination of the absolute position.

Regarding Australia,  here are a few maps that provide different proportioning.

Here is Gleason's Australia:


One from  Maphill:


Another composite "satellite" map:


And then there is Google's etal:


Looking at each of these maps, I  believe, based on expanding lines of  Longitude as one  proceeds South, that the closest match to reality is the composite "satellite" map.
Let me illustrate.

Using the Longitudes provided by the Globe-nauts, running some  lines from North to South from same Longitude valued cities in and north of, and in the south of Australia, the map is  shown as  such:


Now, granted, the lines I have drawn are based on values provided from the Wikipedia pages of those cities I chose as having the same Longitudes, but the point is this:  The composite "satellite" map does show expanding longitudinal lines as one goes further South.  This necessarily implies that this composite map  is more real than the others that show Longitudes that are totally vertical.

The next step is to figure the distance between degrees of  Longitude  in the north of Australia and  compare them  with the distance between degrees of Longitude in the south of Australia.

Certainly places like this will  aid us in our work:  Eyre Highway: the Longest Straight Road in Australia
https://unusualplaces.org/eyre-highway-the-longest-straight-road-in-australia/

To be continued.

BDH

bdhfe wrote:[q

Cassini's survey found that from Perpignan S to Dunkirk N degrees of latitude shortened by around 1/800th Northward. So both Copernican and Newtonian models were incorrect.

His results were checked and no fault found , also backed up by other practical astronomers . Both theories were wrong. The age of "enlightenment" was brought to a halt. Huge controversy ensued .A cover up began .

Must go now but it is worth researching this if you get the time. Will add more later.

TyrannicalSawdustRex,
Thank you for the very interesting information.
Regarding  the latitude shortening when proceeding North along the Paris meridian,  it  would be  good to know  if Cassini was  using Globe-based methods for calculating latitude  or not.

BDH[/quote]


There were no globe calculations at that time. Triangulation survey along the meridian would pick up the shape of earth determined by any change in length of degree of latitude. A scientific survey without bias.

The main instrument used was the transit scope which when aligned with the Pole star would only traverse along the line of meridian upon which it stood i.e. North to South .  It could also give star positions as they reached zenith when aligned vertically from the same position . That allowed the line of longitude to be followed accurately as the survey continued in either direction along the meridian.

Sun position was irrelevant since clocks of the time were not accurate plus the conditions during night were more relevant since the stars provided a means of constant check.

Geovanni Cassini died in 1712 and globe calculations were later devised to map plane triangulation survey on any sized globe one required.

My view is that the original results showed the world the world to be flat and the pole star within a measurable distance although I don't rule out that our plane could also part of a much larger globe.

Basically real science based on experiment and observation was usurped by theoretic claptrap from that point on.