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Offline Bobby Shafto

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Re: The Horizon is Always at Eye Level
« Reply #380 on: June 06, 2018, 10:51:14 PM »
At elevations within the range of Rowbotham's Experiment #15 observations from the Grand Brighton, here's what I saw:



If I were to observe what Rowbotham describes, with gain in elevation from 10' above the water to 75', I should have seen "the uprising surface ... meet the eye-line"

But it did not. The blue line in the bottom picture would be the new "eye-line"



I'm not using a "leveled" clinometer to measure dip here. I'm just observing the horizon using distant islands as an index. But if I gain altitude and I can fix my eye on a spot of land previously hidden that I know is below my level eye-line, then I must be looking across at an angle less than 90 degrees.

The horizon didn't rise to eye-level when I gained elevation.
The distance to the horizon did not remain constant.

I have the advantage here of visible landmarks at or near the horizon that Rowbotham didn't have from Brighton. But even my crude, homemade devices are detecting "dip" at less than 100' above sea level that his clinometer apparently was unable to detect.

Post edit: With the given distances to those islands, the difference between where Rowbotham's predicted "water level rise to eye-line" and the actual horizon is 0.05°. I can attest to the difficulty of measuring such an angular dimension to that degree of granularity. Without the islands for reference, using a clinometer, Rowbotham's error might be understandable since we don't know what kind of instrument he used.
« Last Edit: June 06, 2018, 10:59:09 PM by Bobby Shafto »

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Offline Bobby Shafto

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Re: The Horizon is Always at Eye Level
« Reply #381 on: June 07, 2018, 06:59:01 AM »
From another topic:

If you cannot produce significant evidence for this wild claim, other than fallacious appeals, then you will need to stop making it.

We do generally admit the limits of our knowledge. However, you guys consistently state "this is known" and "the data is consistent" and similar statements. If you are going to make such claims of something being known, then you are expected to demonstrate your claims.

If you cannot demonstrate your claims, that is an automatic lose.

Agreed.

Rather than citing a drawing handbook, an anecdote where it "appears" or "seems" to be true, and a simulated perspective in video games, I challenge anyone to demonstrate the "horizon always at eye level" claim.
« Last Edit: June 07, 2018, 07:03:35 AM by Bobby Shafto »

Max_Almond

Re: The Horizon is Always at Eye Level
« Reply #382 on: June 07, 2018, 07:16:54 AM »
From another topic:

If you cannot produce significant evidence for this wild claim, other than fallacious appeals, then you will need to stop making it.

We do generally admit the limits of our knowledge. However, you guys consistently state "this is known" and "the data is consistent" and similar statements. If you are going to make such claims of something being known, then you are expected to demonstrate your claims.

If you cannot demonstrate your claims, that is an automatic lose.

Agreed.

Rather than citing a drawing handbook, an anecdote where it "appears" or "seems" to be true, and a simulated perspective in video games, I challenge anyone to demonstrate the "horizon always at eye level" claim.

That Wiki page is comically bad. There's not a single demonstration, measurement, photograph, or diagram on it.

Is that really the best they've got? That the horizon "looks like it's at eye level to some people"? One man's musing from 1857? An 'experiment' involving a computer game?

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Offline Bobby Shafto

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Re: The Horizon is Always at Eye Level
« Reply #383 on: June 07, 2018, 08:10:08 AM »
Noticed something while reviewing photographs:



There's a fairway buoy out there I hadn't noticed.



It's tethered about 3.25 miles from my sealevel, 100' and 400' viewing points, and which means it should sit just a little bit in front of the (globe earth) horizon when viewing from close to sea level. It looks like it's about 35' tall (based on the size of the harbor seals basking on its base) though maybe Tontogary can advise.



This is serendipitous and lends itself to being yet another advantage for using this sight line to perform and record horizon observations to assess the "eye level" claim.

From 100' vantage point:


From 400' vantage point:


I'm anticipating clear enough skies and horizons tomorrow to accomplish this test. And if I can time it with some shipping traffic at or near calculated horizon lines, that'll be a bonus.

Offline Tontogary

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Re: The Horizon is Always at Eye Level
« Reply #384 on: June 07, 2018, 11:20:13 AM »
Sorry i cannot help Bobby. I have looked through the different charts, and the height is not mentioned, although i can confirm you have the right buoy by looking at it, and the characteristics are the one charted.

I also looked through the coast pilot books, and the List of lights, which were able to give me a fair amount of detail except the height of the light and the total structure.

From experience I wouldn’t say it is more than about 25 feet tall having been past many of these, and comparing them to our freeboard, but i dont think the height is of any great concern, as i dont think you were trying to measure anything.

Sorry.  :(

Also, if you haven't heard of bronies before, that reflects poorly on your understanding of the world that surrounds you. It's practically impossible not to know about them.

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Offline Bobby Shafto

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Re: The Horizon is Always at Eye Level
« Reply #385 on: June 07, 2018, 09:33:38 PM »
That's alright. Thanks anyway.

I'm anticipating clear enough skies and horizons tomorrow to accomplish this test. And if I can time it with some shipping traffic at or near calculated horizon lines, that'll be a bonus.

And this just isn't going to happen. I can't see marine traffic 20 miles off the coast due to the haze, even though the sky overhead is crystal blue. The Coronados are in the mist, and conditions are just not prime for performing this "experiment."

So, I'm going to table this for a few months and wait for more Fall-like weather. If I'm not over the subject by then, I'll check back in. But I don't think there's anything more to add to the subject until then.

Out.

Offline iamcpc

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Re: The Horizon is Always at Eye Level
« Reply #386 on: June 15, 2018, 07:07:16 PM »
That's alright. Thanks anyway.

I'm anticipating clear enough skies and horizons tomorrow to accomplish this test. And if I can time it with some shipping traffic at or near calculated horizon lines, that'll be a bonus.

And this just isn't going to happen. I can't see marine traffic 20 miles off the coast due to the haze, even though the sky overhead is crystal blue. The Coronados are in the mist, and conditions are just not prime for performing this "experiment."

So, I'm going to table this for a few months and wait for more Fall-like weather. If I'm not over the subject by then, I'll check back in. But I don't think there's anything more to add to the subject until then.

Out.

Have you tried with a telescope by chance?

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Offline Bobby Shafto

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Re: The Horizon is Always at Eye Level
« Reply #387 on: June 15, 2018, 07:57:49 PM »
I don't have one anymore, so no. I don't think that will resolve the issue of atmospheric clouding.

I have a sense that the "horizon at eye-level" claim may be diminishing in its certainty and centrality to flat earth reasoning.  In fact, the EA discussion has revealed that if it is to be an explanation for observed phenomenon on a flat earth, the horizon can't always be at eye-level but would also drop with elevation.

I'll still collect and post observations after conditions here are right. I may even post a video.

Something I've become acutely aware of those is the uncertainty of correctly sighting the horizon when there are strong inversion layer or ducting effects. I have yet to see a day yet when there hasn't been a significant inferior mirage. If you're just looking at a sea/sky horizon, you wouldn't know there was a mirage. A feature like an island or a lighthouse or a ship at sea (or the sun) reveals the mirage. And then, you have to figure out where above that apparent horizon the real horizon is. 

Since the goal of this wasn't to measure "dip" of the horizon but to detect if there is "dip" or not. My takeaway so far is that at least above 100' elevation, any dip will be enough to exceed the mirage effect that presents an appearance of a lower horizon. But I think this needs to be more clearly understood by both flat and round earth defenders out there with their P900s and producing supporting and debunking videos. I haven't really seen any address the mirage and what it means when assessing whether or not earth's curvature is what's obscuring things at a distance.

Anyway, no. I've not used anything more magnifying than my DLSR's pedestrian zoom.

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Offline Bobby Shafto

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Re: The Horizon is Always at Eye Level
« Reply #388 on: September 01, 2018, 10:01:00 PM »
Been awhile since I've addressed this topic. Haven't forgotten, but still waiting for the off shore marine layer haze to take its fall/winter vacation and afford me 50+ mile clear SoCal horizon views for performing the final horizon level sightings.

In the meantime, saw this in the JTolen Media 1 video we've been discussing in the Sphere/Flat "challenge" discussion topic.

In the intro section of that IR imagery of San Jacinto, JT references using a theodolite app from an aircraft flight from Buffalo to Chicago, and noting that he saw the water of Lake Erie above where the globe earth horizon line should be (-3.4° from level sight at 37,000').



I had glossed over most of that background stuff since there wasn't much detail to analyze. But Tom Bishop challenged me to address the Salton Sea sighting JT took seen around the 2:15 mark of that video. Since then, I've looked more closely at the other examples of observations he made where he believes the earth is appearing to be flat vice globe.

As with the San Jacinto case, I don't believe JT's image from the aircraft is supporting the argument he believes it does. But before I dive into my analysis of that theodolite-app annotated image, I'd like to invite Tom to take a closer look. Particularly given the critiques he has made in this topic of my attempts at sighting on the horizon, is JT's example here supportive of a flat earth or of a debunking of the globe?

(I only address this to Tom since he's sometimes willing to come forward on these. Of course, the invitation is open to anyone and not just Tom.)

« Last Edit: September 01, 2018, 10:04:15 PM by Bobby Shafto »

Max_Almond

Re: The Horizon is Always at Eye Level
« Reply #389 on: September 02, 2018, 04:45:40 AM »
I don't get this. His image says "we should not see the ground at an angle of -3.3 degrees if the Earth is a sphere" when that's (about) exactly what we should see. And if the Earth was flat, his theodolite should be reading just below 0 degrees.

If he's calibrated correctly, everything he's done points to the horizon being substantially below eye level and to a spherical Earth.

Is he pulling legs? Parodying flat earthers?

HorstFue

Re: The Horizon is Always at Eye Level
« Reply #390 on: September 02, 2018, 12:54:38 PM »
I don't get this. His image says "we should not see the ground at an angle of -3.3 degrees if the Earth is a sphere" when that's (about) exactly what we should see. And if the Earth was flat, his theodolite should be reading just below 0 degrees.
Form  the video: "I placed the cross-hairs down to -3.3°, which is where the horizon should be."  (on a globe earth).
But the cross-hairs point lower than the horizon.

If he's calibrated correctly, everything he's done points to the horizon being substantially below eye level and to a spherical Earth.
That's the point: Calibration of the inclinometer.
How can you calibrate a level instrument on a moving aircraft, a car, a ship? Never!
What you measure is not the "vertical" defined by gravity. Every craft, while moving, experiences additional forces and so accelerations. It could accelerate or break. It could follow a curved path - what I assume is the case in the video. A curved path will create a centrifugal force, which will result in an additional acceleration perpendicular to the gravity vector. Gravity and centrifugal force combined will give a new "local fake vertical", which is not parallel to the real "vertical".

I did not fly an aircraft so far, but many times sailed yachts, A sail yacht, a boat will never go "straight" by itself. All the time you have to correct the course, turning the steering wheel small angles left or right any few seconds, even on dead plane water with no waves and no wind. The resulting course  is not a straight line, but a sequence of flat curves.
I think, same applies to an aircraft. These flat curves generate centrifugal forces, making any level measurement void.

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Offline Bobby Shafto

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Re: The Horizon is Always at Eye Level
« Reply #391 on: September 02, 2018, 04:17:52 PM »
I don't get this. His image says "we should not see the ground at an angle of -3.3 degrees if the Earth is a sphere" when that's (about) exactly what we should see. And if the Earth was flat, his theodolite should be reading just below 0 degrees.
Form  the video: "I placed the cross-hairs down to -3.3°, which is where the horizon should be."  (on a globe earth).
But the cross-hairs point lower than the horizon.

I get what he's trying to do. He's not sighting the crosshairs on anything. He's just tilted down until he got the 3.3-3.4° "dip" angle that would be the calculated angle between a horizontal line and the line tangent to the earth, coincident with the horizon, from about 37,000'. That's correct.

The crosshairs guides on the screen are static. As the phone tilts, the scale on the right scrolls to display the amount of tilt away from horizontal. So (if calibrated and if accurate) the crosshairs when the gauge is reading 3.3° would be on the globe horizon line from 37,000'.

In the image, he's seeing Lake Erie above the horizon (cross hairs).

Isn't he?

Calibration is certainly an issue. So is precision with these apps. I have Theodolite on my phone, and back in this thread you can find examples of me trying to use it. But I was trying to detect "dip" of around the granular limit of the app's scaling (+/- 0.1°) and found it very difficult, even with a tripod, to measure to that degree of precision.

Not to mention that constant calibration and accuracy of the accelerometers of the phone. It quickly became novelty tool for what I wanted it for. From an airplane in flight, I don't see how you could trust the dip angle measurement down to the tenth of a degree. It's possible he took video and just captured a frame in which he had the dip close, but that still doesn't ensure accuracy of the reading.

However, 3.3 or 3.4° I suppose is close. His point can be made even if the calibration is off a couple tenths of a degree since he's at an elevation where whole degrees matter more than tenths.

What I hope to draw focus on isn't the accuracy of the tool, but his interpretation of what he's seeing. I guarantee you if I had been on a flight, sighted a horizon, put the crosshairs on it and it read out -3.4° and posted it on this board as evidence that the horizon dips and the earth is curved, Tom (at least) would be all over it. As I've said before, I invite the critiques. It's good to be challenged. But critique should be balanced. The same degree of inspection and critique should be made for any argument or evidence presented for either side of the flat/globe debate. What I was hoping from Tom was a recognition that JT's slide from that video may not be supportive of what he's claiming.

Tom is not unique. We all tend to latch onto, without skepticism, evidence claims that support what we believe. And we'll put a magnifying glass to those that contradict what we think we know. If you're only interested in "winning" a debate or strengthening an affirmed tenet, then that makes sense. But if you're are being honest about wanting to get at the truth, then that's misguided approach. You have to be as skeptical of evidence for either side and as rigorous in evaluating it.

I received a lot of critique (some constructive) on my attempts to detect (not measure) horizon dip. I would expect a truth seeker to apply that same degree of rigorous questioning of evidence presented to claim the horizon is at eye level. 

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Offline Bobby Shafto

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Re: The Horizon is Always at Eye Level
« Reply #392 on: October 09, 2018, 10:40:39 PM »
Ditching the wire cube. Made sense to me, but too hard to explain and too unwieldy to tote about and set up. (Also, it drew crowds and made me face a lot of questions I'd rather not have to answer.)

On a lark this past weekend, I cobbled this together from some surplus irrigation parts (12" long 1/2" threaded PVC pipe and two barbed elbows). Bought a 10' length (only need about a foot or two) of 1/2" ID vinyl tubing and, voila: a portable water level sighting tool. Found a way to clamp it onto a travel tripod, and with a little water and food coloring....






Check of the horizon from 90' from here:





and from 360' from here:




I like it.

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Offline RonJ

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Re: The Horizon is Always at Eye Level
« Reply #393 on: October 10, 2018, 04:27:34 AM »
Checkout the theory of operation of the sextant.  You will find there that there is a height of eye correction needed in your measurement.  On the last ship I was on I think the height of eye was about 130 feet.  That meant if you were standing on a bridge wing taking a sighting with your sextant you had to compensate the measured angle with the height of eye.  If you were to be on a small sailboat taking a measurement at the identical time as someone else on a large ship you would get a slightly smaller measured angle because you are closer to the level of the horizon on a small sailboat.  What you are actually measuring is just the angle of the navigation body above the horizon and a very specific time.  You need the time very accurately because the earth rotates under the star.  When you have an angle from your sextant and your time to the second you can enter the navigation charts (ephemeris) with this data and determine the zenith point of the body that you just measured.  The zenith point is that point on the earth that is directly below the body.  Once you have that position you can make a mark on your chart and draw a circle with a radius determined by the measured angle.  Now after all that work all you have is a line of position.  Your ship's position should be somewhere on that line.  To get your actual position you will need to repeat the same procedure on another star, planet, or the moon.  After you plot the second body you will have your position where the two lines cross.  You could also 'shoot' the sun and determine it's highest point in the sky by measuring it at local apparent noon.  This will give you some information about your position as well.  Few people do this aboard ship these days except for the maritime academy cadets who need to learn celestial navigation as part of their training.  GPS is the primary means of navigation, but using a sextant can teach you a whole lot about the Sun, moon and stars and they way they behave.  This all assumes that the earth is a sphere. Finally, the Horizon is not at eye level.  On any practical measurements the angle difference is very small but if you don't compensate for your height of eye above the horizon your determined position could be off by several miles.  That's no problem unless you are trying to avoid that spot where the rocks are only a few feet underwater.   
You can lead flat earthers to the curve but you can't make them think!

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Offline AATW

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Re: The Horizon is Always at Eye Level
« Reply #394 on: October 10, 2018, 10:38:52 AM »
Ditching the wire cube. Made sense to me, but too hard to explain and too unwieldy to tote about and set up. (Also, it drew crowds and made me face a lot of questions I'd rather not have to answer.)

On a lark this past weekend, I cobbled this together from some surplus irrigation parts (12" long 1/2" threaded PVC pipe and two barbed elbows). Bought a 10' length (only need about a foot or two) of 1/2" ID vinyl tubing and, voila: a portable water level sighting tool. Found a way to clamp it onto a travel tripod, and with a little water and food coloring....






Check of the horizon from 90' from here:





and from 360' from here:




I like it.
Outstanding work, as always.
I'm sure in the light of this the Horizon Always At Eye Level page will be amended and FE Theory will be moved on immeasurably.
Tom: "Claiming incredulity is a pretty bad argument. Calling it "insane" or "ridiculous" is not a good argument at all."

TFES Wiki Occam's Razor page, by Tom: "What's the simplest explanation; that NASA has successfully designed and invented never before seen rocket technologies from scratch which can accelerate 100 tons of matter to an escape velocity of 7 miles per second"

Offline iamcpc

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Re: The Horizon is Always at Eye Level
« Reply #395 on: October 11, 2018, 07:13:17 PM »
Outstanding work, as always.
I'm sure in the light of this the Horizon Always At Eye Level page will be amended and FE Theory will be moved on immeasurably.

No way. This is not the first person to have demonstrated observations that suggest that the horizon MIGHT not ALWAYS be at eye level.

I don't have a link to the post but someone can just push this away as optics. The horizon is at eye level it just that the optics don't reflect it.

https://www.metabunk.org/how-to-show-the-horizon-is-below-eye-level-using-actual-eyes.t8845/


I have never heard anyone who believes that the horizon always rises to eye level look at the observations made and say something like 99% of the time the horizon rises to eye level. Nope. Based on these observation I've never seen anyone even concede 1%.
« Last Edit: October 11, 2018, 07:31:53 PM by iamcpc »

Max_Almond

Re: The Horizon is Always at Eye Level
« Reply #396 on: October 12, 2018, 06:34:00 AM »
I have never heard anyone who says they believe that the horizon is always at eye level post a photo with some actual measurements in it: usually they just figure 'cos it's in the middle of the frame, that means it's at eye level. Then they don't understand when you tell them it doesn't work like that.

This is Flat Earth 101. If they don't understand the basics, how are they going to understand more complex things?

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Offline AATW

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Re: The Horizon is Always at Eye Level
« Reply #397 on: October 12, 2018, 10:13:15 AM »
I have never heard anyone who says they believe that the horizon is always at eye level post a photo with some actual measurements in it: usually they just figure 'cos it's in the middle of the frame, that means it's at eye level. Then they don't understand when you tell them it doesn't work like that.

This is Flat Earth 101. If they don't understand the basics, how are they going to understand more complex things?
I think this is part of their over-reliance of the senses.
The horizon looks about eye level even at altitude, ergo they conclude that it is at eye level.
Many attempts have been made to explain that there are things that we can't perceive but that we can measure - and this is one of them.
It doesn't seem to have made much impact though.

Obviously I was kidding above, no ground will be conceded here, no experiments will be done, no observations made.
This is where Tom's lament about lack of a research budget for FE falls flat, this is something which could be done quickly and cheaply - as Bobby has demonstrated - and the result would move FE Theory on. But they claim they're too busy so nothing moves forward which is why the same discussions go round and round.
Tom: "Claiming incredulity is a pretty bad argument. Calling it "insane" or "ridiculous" is not a good argument at all."

TFES Wiki Occam's Razor page, by Tom: "What's the simplest explanation; that NASA has successfully designed and invented never before seen rocket technologies from scratch which can accelerate 100 tons of matter to an escape velocity of 7 miles per second"

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Re: The Horizon is Always at Eye Level
« Reply #398 on: October 12, 2018, 04:23:42 PM »
I have never heard anyone who says they believe that the horizon is always at eye level post a photo with some actual measurements in it: usually they just figure 'cos it's in the middle of the frame, that means it's at eye level. Then they don't understand when you tell them it doesn't work like that.

This is Flat Earth 101. If they don't understand the basics, how are they going to understand more complex things?
Bobby’s experiment with the water level sighting tool is excellent as usual. But the problem as usual is the chain of inference required to address ‘Horizon is Always at Eye Level’. The inference is something like this:

1. We can draw an imaginary straight line between the two menisci in the two tubes. [Problem: is an imaginary line a real line, is Euclidean geometry true, what is a ‘meniscus’]

2. This line must be parallel to the surface of the (purportedly flat) earth. [Problem: this follows from the FE claim that water ‘finds its own level’ – whatever that means]

3. If we place our eye so that it is on the ‘line of sight’ connecting the two menisci, then anything on that line must be parallel to surface of [flat] earth [Problem: what exactly is a ‘line of sight’]

4. A straight line drawn in the surface of the earth parallel to the imaginary line will, by the laws of perspective, appear to converge with that imaginary line when it reaches the horizon [Problem: what exactly are ‘laws of perspective’? Are there FE laws different from RE laws.]

For each step there is the problem of explaining the terms, and there are four steps in the chain. My estimate that any FE discussion requiring more then two steps will fail. The other side will stop responding at some point, without any conclusion reached.
« Last Edit: October 12, 2018, 04:25:26 PM by edby »

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Offline Bobby Shafto

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Re: The Horizon is Always at Eye Level
« Reply #399 on: October 12, 2018, 11:33:05 PM »
Bobby’s experiment with the water level sighting tool is excellent as usual. But the problem as usual is the chain of inference required to address ‘Horizon is Always at Eye Level’. The inference is something like this:

1. We can draw an imaginary straight line between the two menisci in the two tubes. [Problem: is an imaginary line a real line, is Euclidean geometry true, what is a ‘meniscus’]

2. This line must be parallel to the surface of the (purportedly flat) earth. [Problem: this follows from the FE claim that water ‘finds its own level’ – whatever that means]

3. If we place our eye so that it is on the ‘line of sight’ connecting the two menisci, then anything on that line must be parallel to surface of [flat] earth [Problem: what exactly is a ‘line of sight’]

4. A straight line drawn in the surface of the earth parallel to the imaginary line will, by the laws of perspective, appear to converge with that imaginary line when it reaches the horizon [Problem: what exactly are ‘laws of perspective’? Are there FE laws different from RE laws.]

For each step there is the problem of explaining the terms, and there are four steps in the chain. My estimate that any FE discussion requiring more then two steps will fail. The other side will stop responding at some point, without any conclusion reached.

This experiment is about as zetetic as it can get. It doesn't require expensive equipment. Anyone can do it. And the possible outcomes are bifurcated and agreed upon: if the horizon is always at eye level, the surface is flat. If the horizon dips, the surface is convex.

Though I did anticipate the results would show that the horizon dips and that the earth's surface was convex, I didn't make that prediction nor set out to bias the experiments to favor dippage. When the results were ambiguous, I posted them. When there was uncertainty about whether or not I was seeing the horizon, I admitted that. 

But in the end, I feel that these observations showed that the horizon does, in fact, drop from level sight as elevation increases. It doesn't seem very zetetic to me to, ex post facto, reject the observations for a litany of reasons without offering ways to better perform them. That's like having the bias that is supposedly the problem with the scientific method. The zetetic is not supposed to be looking for a result of flatness and then trying to find reasons why the results are not what one wants or expects.

These homegrown methods aren't attempting to show how much the horizon dips. Only whether it does or doesn't. If the methods I've employed are not adequate, then what would be? I'm game for any suggestions.