[Bobby Shafto]

I think you will run into a road block on what is a true horizon.

In GE we can know that there is a horizon, and calculate its distance, but on a FE it is completely subjective, as the ground, sea whatever rises up until it gets fuzzy, and disappears into .......... well something!

There's got to be some way to tell, otherwise how can you ever claim that it always rises to eye-level? It would be a tautology to claim it always rises to eye-level, and if it doesn't, you're not seeing the horizon.

I think once we get through the annual "May Gray" and "June Gloom" that is common this time of year, I'll have opportunities where there's no doubt the sky at the horizon "convergence" is true and the horizon is as high as it's going to get for any given elevation. But if there's some criterion for assessing when what we're seeing is a "true horizon" per FE, I need to consider that. I just need it explained to me.

[Tontogary]

I think you will run into a road block on what is a true horizon.

In GE we can know that there is a horizon, and calculate its distance, but on a FE it is completely subjective, as the ground, sea whatever rises up until it gets fuzzy, and disappears into .......... well something!

There's got to be some way to tell, otherwise how can you ever claim that it always rises to eye-level? It would be a tautology to claim it always rises to eye-level, and if it doesn't, you're not seeing the horizon.

I think once we get through the annual "May Gray" and "June Gloom" that is common this time of year, I'll have opportunities where there's no doubt the sky at the horizon "convergence" is true and the horizon is as high as it's going to get for any given elevation. But if there's some criterion for assessing when what we're seeing is a "true horizon" per FE, I need to consider that. I just need it explained to me.

That is my point, the description of the horizon is sufficiently fuzzy (forgive the pun) that if you show measurements that show a dip of the horizon you will run into the argument that as it is “proved” in EnaG that the horizon rises to meet the eye line, then your measurements could not possibly have been taking the horizon.

It is an argument which is based on a debatable proof, but it will still be difficult to tell if you were taking a clear horizon. In my mind EnaG does not prove that the horizon rises to eye level, but to FE believers they think it does, so you will be at a stalemate.

I have measured horizon to horizon, and verified my result, only to come across the exact same objection, that i cannot prove the horizon was sharp, or in fact real! I could take a picture, which could be claimed as fake, and even if i had witnesses, the claim could be made that the hoizon to a casual observer seemed false....

If we can get round this horizon part, we should get to the bones of the matter.

[Bobby Shafto]

This is a 568x137px segment of the 1600x900 original image.
These pixel measurements are based on that resolution, but I've zoomed it to about 2x original size to make it easier to see.

It looks like the cube was canted slightly, with a 1-2 pixel "roll" to the left from horizontal as evidenced by the yellow transversal drawn from weld to weld of three center most orthogonal wires.
The level sight line shows a "dip" of the horizon on the right of 4 px, but on the left of only 3px.
For comparison (and to show how it matters where you determine the water level edge is from the vinyl), I drew in 3px, 4px and 5px vertical lines from the apparent horizon line. In set up, I had tried to sight along the middle of that thick blackish blue area at the top of the water level in each tube. That's 4px above apparent horizon.

Personally, I'm pretty amazed this is as close to straight as it was. 1-2 pixels of height across 568px of image isn't too bad for a homemade, non-precision instrument. I think if I'd have been able to use the plumb bob, I might have corrected for that slight cage/cube roll.

And I think this gives me better confidence to sight along the middle or bottom of that dark line of the water level rather than the top. I believe this line is a 'leeching" (not the right word; "creeping" maybe?) effect as the water interacts with the interior surface of the vinyl tubing, giving it bit of concavity at the inner edge. If there's an additive or a kind of fluid that counters this edge-creep, I'll use it. (I'm not a chemist, so I don't know the reason for this or what might solve it. Perhaps antifreeze?)

Edit: It's called 'the meniscus'. I probably should have learned this in high school, but I don't remember.

[Bobby Shafto]

^ Skim-reading a bit more, the meniscus exists whether it's concave, convex or flat. What I want is flat, or a 'wetting angle" of 90° so that the fluid isn't convex or concave where it meets the vinyl tubing.

Lots of great descriptions but no simple lists or tables of what to use instead of water or in addition to water to get that wetting angle closer to 90° and get a sharper demarcation of the water level.

Unless anyone here knows a thing or two about this, I'll experiment. Maybe transmission or brake fluid. Maybe baking soda dissolved into the water. Or Windex? Rain-X? (Might be the opposite of what I want)

[douglips]

It's not a matter of picking the right fluid, it's a matter of picking the right fluid/solid system. The surface of the cylinder has a say as well into what the contact angle is.

https://en.wikipedia.org/wiki/Contact_angle

What about having small objects that can float on the surface and using them to disambiguate?
What about using Rain-X or something to make the surface of the cylinders hydrophobic?

[Bobby Shafto]

It's not a matter of picking the right fluid, it's a matter of picking the right fluid/solid system. The surface of the cylinder has a say as well into what the contact angle is.

https://en.wikipedia.org/wiki/Contact_angle

What about having small objects that can float on the surface and using them to disambiguate?
What about using Rain-X or something to make the surface of the cylinders hydrophobic?

I crossed that out above, thinking that by "hydrophobic" the opposite might happen and I'd get a convex surface level. Rain-X makes the water bead on the glass windshield. Not sure what it would to with plastic/vinyl.

I actually tried water+alcohol mix. Seemed to improve the wetting angle, but maybe that's just wishful thinking. I'll try Rain-X. See what happens.

[hexagon]

But you have to understand it, if you want to understand why they don't believe in your argumentation or your experiments…

I don't think I do. The objective is to simply verify or refute the claim that "the horizon is always at eye-level." 

I would love to understand the explanation for why that would be so on a flat surface earth, but it's not necessary that I do in order to test the claim.

Now, if I demonstrate that the horizon is NOT always at eye-level, any dispute will have to come from test set up or the method with which I attempt to observe it. But such issues have nothing to do with understanding why the horizon is always at eye-level. 

If it can be shown that the horizon drops below level as elevation increases, then that doesn't mean it'll refute a flat earth. It will just refute the horizon claim. Flat earth proponents will have to theorize another explanation for why the horizon appears as it does.

On a convex curved surface, the horizon will drop from level.
How it appears on a flat surface? I'm interested, but that's not my concern in this effort. I just want to see if it drops or not.

If there are problems with setup or method, I've invited feedback numerous times. I feel confident I'm being more careful, meticulous and guarded against obtaining a preferred outcome than was Samuel Rowbotham, but if there's a technique or method he used to verify the horizon was always at eye-level that I am missing, I encourage anyone to speak up and allow me the opportunity to include it.

If you refuse to understand their claims, you cannot disprove them. What you are doing is to show that the extrapolation of the parallel lines in your pictures are meeting at one point above the apparent horizon due to perspective. But that is nothing any flat earth believer is denying. What you have to proof is, that the extrapolation as such is valid. That's something very, very different. As I explained above, anything regarding perspective of objects at or near the horizon is constructed from the vanishing point back towards you in the context of so-called flat-earth theory.

You may reply, that this should be equivalent. Yes, but only if the extrapolation is linear. But no flat earth believer claimed that, they simply don't know. So, you can make your fancy device as sophisticated as you like, it will not be accepted as disprove, because it does not target the fundamental question.   

[Bobby Shafto]

If you refuse to understand their claims... 

I'm not refusing. I don't understand the basis for the claim.

The claim is the horizon is always at eye-level. I understand what that means. I don't understand the explanation for why that should be.

What I'm saying is I don't have to understand why. I'm not refusing. I'd love to know. I just don't think it matters in order to check to see whether or not the horizon actually does remain at eye-level.

Think of it like this absurd example.
You say dropped toast with jelly always lands jelly-side down.
That doesn't sound right to me. I say it ought to be 50/50.
Let's test your claim.
You claim that the reason it's always jelly-side down is because "humankind is just materialized color operating on the 49th vibration."
I scratch my head and wonder what that means.
But does it have any bearing on checking to see if "always jelly-side down" is true?
Do I need to understand what materialized color means and has to do with the claim in order to check whether or not toast really does always land jelly-side down?

[Tumeni]

^ Skim-reading a bit more, the meniscus exists whether it's concave, convex or flat. What I want is flat, or a 'wetting angle" of 90° so that the fluid isn't convex or concave where it meets the vinyl tubing.

Lots of great descriptions but no simple lists or tables of what to use instead of water or in addition to water to get that wetting angle closer to 90° and get a sharper demarcation of the water level.

Unless anyone here knows a thing or two about this, I'll experiment. Maybe transmission or brake fluid. Maybe baking soda dissolved into the water. Or Windex? Rain-X? (Might be the opposite of what I want)

The larger the surface area of the water/fluid, the less significant the meniscus. Wider tubes, or a single large tray ...

[Tumeni]

If you refuse to understand their claims, you cannot disprove them. What you are doing is to show that the extrapolation of the parallel lines in your pictures are meeting at one point above the apparent horizon due to perspective. But that is nothing any flat earth believer is denying.

What are the flat-earth believers denying, then?

But no flat earth believer claimed that, they simply don't know.

They 'don't know'? But what claim are they making, if they don't know?

So, you can make your fancy device as sophisticated as you like, it will not be accepted as disprove, because it does not target the fundamental question.   

What IS the 'fundamental question', then?

[hexagon]

If you refuse to understand their claims, you cannot disprove them. What you are doing is to show that the extrapolation of the parallel lines in your pictures are meeting at one point above the apparent horizon due to perspective. But that is nothing any flat earth believer is denying.

What are the flat-earth believers denying, then?

But no flat earth believer claimed that, they simply don't know.

They 'don't know'? But what claim are they making, if they don't know?

So, you can make your fancy device as sophisticated as you like, it will not be accepted as disprove, because it does not target the fundamental question.   

What IS the 'fundamental question', then?

The fundamental question is, if you could linearly extrapolate from your position to infinity. Because that is what you are doing here. You take some apparatus, you align it, take a picture and the you draw some straight lines into the picture. This is a linear extrapolation over a very great distance.

The flat earth guys say, we don't know if we can do this extrapolation. We are looking onto this from the other side. We put the vanishing point at some fixed distance and then what they call perspective lines goes away under a fixed angle from this point. And if this leads to some contradictions from what you observe from your point of view then reason for this might be, that the assumption of linear extrapolation is not valid of large distances. That's what they mean if they talk about limits of Euclidean geometry and discontinuities.

What you have to do now, is to proof that this linear extrapolation is justified and valid. Because otherwise you cannot proof that there is a contradiction between your experiments and their understanding of perspective, vanishing point, horizon, etc. 

And that's in principle the same for all physical explanations of astronomical observations. They all assume that the laws of physics are same at every point in space. Of course there is no indication and reason to not believe this, but in the end this cannot be proved.     

[Bobby Shafto]

The fundamental question is, if you could linearly extrapolate from your position to infinity.

The fundamental question is, "is the horizon always at eye level?"

Is it? How do you know? How do you test to see if that's true?

Here's a flat earth demonstration using water level to claim the horizon does maintain at eye-level.
https://www.youtube.com/watch?v=IRTCCEB_QIg&t=177s

Here's a globe earth guy using the same technique to claim it doesn't
https://www.youtube.com/watch?v=NqOQ_BCtqUI&t=6s

How can they come to different conclusions using the same technique?

I'd like to improve on the method.

Seeing this photograph gave me the idea to complement the water level with a squared frame of reference for lines of perspective:



Perspective, as in drawing 3D depth on a 2D canvas where art students are told the vanishing point is always on the horizon, is the flat earth reason given for the phenomena on the horizon by flat earth (sinking sun, ships disappearing hull first). So perspective plays a key role in the flat earth explanation. I'm sorry that I can't grasp the explanation for why that is so, but I can grasp a definitive claim like "the horizon is always at eye level" regardless of the rationale for such a claim.

So, is the horizon always at eye level? Does the perpendicular plane vanishing point for an observer at any elevation always coincide with the horizon?

It's not my claim. I'm just testing to see if it's true. If there's some way I'm misunderstanding the claim, and a 90 degree from plumb view is not where the vanishing line of a horizon will always be, regardless of elevation, then a flat earther endorsing the "the horizon is always at eye level" needs to explain why not.  If the horizon can change angles depending on what I can see at varying distances without me doing anything to change my elevation, then how can it always be at eye level?

If there's something about my ignorance in understanding flat earth explanation for horizon and vanishing point that renders this method I've chosen flawed, then that needs to be explained to me. So far, I've not seen anyone try. The closest is the challenge of whether or not I'm looking at the "true horizon." Well, how do I know that. Explain that to me so I can incorporate it.

[hexagon]

What you prove is, that lines you draw along parallel lines in a picture meet in one point and this point is always above the line where the sky apparently meets the see if the optical axis of your camera is parallel to the tangent to the earth surface at the position of the camera. That's a consequence of optical imaging of 3D surrounding onto a 2D plane. And the meeting point is the vanishing point according the usual definition of perspective.

Now look into EnaG and how the vanishing point and everything related to this is defined there. It is very different. And it leads to some contradictions to your observations. But this contradiction vanishes if you no longer assume that there is a linear relation between that what is far away and nearby you. Somewhere in between everything is changing nonlinear in such away that the contradiction is solved. That doesn't sound quite rational, but how do you really know that it is not the case?

So prove the linearity and your experiment gets validity.

But what would be a valid proof? I don't know. Regarding the real position of the sun it is quite easy. You just go straight until you approach the sun. But how do you prove that you are really going straight? How do you convince someone who only believes it what he called a direct proof? It's not an easy task...     

[Bobby Shafto]

Well, until a flat earth proponent steps forward and objects to this method on the grounds you say he or she could, I'm proceeding as if it's acceptable; because I can't play devil's advocate for them for an explanation that makes no sense to me.

I've repeatedly put the invitation out to critique this method, and the best (only one, really) offered so far is Tom Bishop's question about how I know I'm sighting the "true" horizon, to which I respond, how does a flat earther know (such as Samuel Rowbotham)? And instead of critiquing the method, he's critiqued its execution.

So, if there's a fundamental disparity between my understanding of how perspective lines should positively complement a level sighting survey and what the flat earth explanation for why the horizon must always be at eye-level that renders this wire cube apparatus pointless, I wish someone would tell me, and try to help me understand why.

[Tontogary]

Bobby, that seems to be the problem, i.e. that you will not get an answer to the difficult questions (and sometimes simple ones too!)

Most of the time, if you are answered, you are directed to the chapters of EnaG, or directed to a further thread or directed to a You tube video.

In the case of EnaG, references back to there are pretty tortuous as there is almost no proofs of anything contained in that work (of mostly fiction), but this will be held up as all the proof you need, and you will be told that the experiments all have been proven..... not so, and not the case. I have read EnaG, and really struggle to find any set of observations without errors of principle or errors of application of principles.

Being directed to previous threads again is rather less likely to answer your questions, other than to be confronted with other un answered questions, and normally a petering out of the thread when there are very few FE posters.

As for the you tube videos, i rather gave up watching the rankings of lunatics, or complete mishmashing of facts with fantasies, and pseudoscience that abound there as proofs of various things.

Ultimately if asking questions you are likely to be disappointed, but still I do applaud your taking the time to actually do something to try understand what is being told to you against what modern science tells us. I only wish some of the FE posters here would actively try to post some experiments as well to put across their side.

[hexagon]

Well, until a flat earth proponent steps forward and objects to this method on the grounds you say he or she could, I'm proceeding as if it's acceptable; because I can't play devil's advocate for them for an explanation that makes no sense to me.

I've repeatedly put the invitation out to critique this method, and the best (only one, really) offered so far is Tom Bishop's question about how I know I'm sighting the "true" horizon, to which I respond, how does a flat earther know (such as Samuel Rowbotham)? And instead of critiquing the method, he's critiqued its execution.

So, if there's a fundamental disparity between my understanding of how perspective lines should positively complement a level sighting survey and what the flat earth explanation for why the horizon must always be at eye-level that renders this wire cube apparatus pointless, I wish someone would tell me, and try to help me understand why.

If you don't understand their view on perspective and how they construct perspective lines read Chapter XIV of EnaG. As you will see (and it's even written there) that doesn't goes along with the usual way perspective works. If you want to understand why a flat-earth believer doesn't care about this contradiction, search the forum for "Euclidean geometry".

Yes, your experiment is very nice, but it only demonstrates what is obvious anyway and known to anyone who deals with perspective, but still will not convince any flat-earth believer, because they take EnaG for granted and solve any contradiction by questioning the universal validity of Euclidean geometry, which means continuous linearity. Prove that, and they will have some trouble to maintain their opinion on perspective. Everything else is a waste of time and effort.   

[Bobby Shafto]

I’m trying to absorb what hexagon is saying. Eye-level is a key to the horizon question. Any test relies on getting that level correct before seeing if the horizon matches it.

Water leveling is a method that’s been tried, and the only question about it seems to be its execution.

There are an infinite number of vanishing points from any particular ocular position. There is only one vanishing plane on a horizontal axis. All horizontal vanishing points (again, infinite) will fall only on that plane. So, if my cube apparatus is squared and perpendicular to a plumb line to the ground, how is the resulting vanishing plane not useful to compare against a horizon line, whether you hold to globe geometry or flat earth rationale? The disagreement is over horizon, not the vanishing plane itself. Isn’t it?

If FE reasons the horizon equals vanishing plane, that’s based on some explanation of why we see a horizon, not on what constitutes a horizontal vanishing plane. If that’s not correct, and a vanishing plane has other factors besides ocular position and orientation, then I can see what hexagon’s point might be.

But if it’s the horizon explanation, then I don’t comprehend why that matters. All that should be of concern for a test like this is if horizon plane = vanishing plane in observation. The cube is to help us identify the horizontal vanishing plane. I know FE has a fundamentally different explanation for the horizon. I’m unaware that there could be a fundamental departure in the concept of perspective and vanishing planes.

[Bobby Shafto]

If you don't understand their view on perspective and how they construct perspective lines read Chapter XIV of EnaG. As you will see (and it's even written there) that doesn't goes along with the usual way perspective works. If you want to understand why a flat-earth believer doesn't care about this contradiction, search the forum for "Euclidean geometry".

Well, I’m in wait line hell at the DMV, so I’ve got the time. I will.

Yes, your experiment is very nice, but it only demonstrates what is obvious anyway and known to anyone who deals with perspective, but still will not convince any flat-earth believer, because they take EnaG for granted and solve any contradiction by questioning the universal validity of Euclidean geometry, which means continuous linearity. Prove that, and they will have some trouble to maintain their opinion on perspective. Everything else is a waste of time and effort.

What’s not obvious is ‘level’. Getting confidence as to what the level ocular horizontal benchmark plane is is what the setup is supposed to accomplish. The intersection of a level sight line from the water leveler with perspective lines from a horizontal ocular view plane gives us the “eye level” against which “horizon” can be compared to determine if they are, in fact, equivalent for all elevations.

If this is no good because perspective concepts (not horizon phenomena) are fundamentally different, then I do need to understand that. I’ll read.

[hexagon]

In terms of the generally accepted view on perspective, it is obvious that the horizon is always below eye-level. Your eye is above ground, so the ground (if it is flat as the sea) is always below eye-level. The horizon is the line where the sky apparently meets the ground, therefor also the horizon is always below eye-level.

There are two prerequisite in this argumentation, first the horizon is at finite distance, second you are looking straight, parallel to the tangent of the earth at your position. The only possibility for the horizon to meet eye-level would be, if the distance to the horizon would be at infinite distance.

Notice that I have not assumed a globe earth. A globe earth only enhances this effect due to the dip towards the horizon line which compensates partly for the apparent perspective uplift of the horizon line. It would be the same on a finite plate under a spherical sky, but, depending on the size, the horizon would maybe a bit closer to eye-level, but still always below.

That's a very obvious consequence of how perspective works. Does't need any experimental proof.   

[Bobby Shafto]

I keep rereading the  sections “why the ship’s hull disappears before the masthead” and “perspectives at sea” and though it sounds like he’s describing perspective as I understand it, he’s applying it in a way that is nonsensical to me. I get his argument about equidistant lines, but I can’t for the life of me deduce how he’s demarcing the horizon.

Each example, the surface appears to slope up to eye level, but then run parallel to (or coincident upon)the eyeline.

But how is that point figured? What’s happening here?

What determines the point at which the ground stops its apparent upward slope? Where does that H point that marks the horizon occur? Is dependent and how far above you the object lost to the horizon is? In other words, there is no horizon point. It’s a variable. The tops of tree are lost to the “horizon” further away than the trunks are?


What is determining where the red line appears to stop sloping upward and the blue line is level?

Is H variable, even if I’m not changing my height over the ground?