[Tom Bishop]

If the water levels in the tubes line up, the camera can't be anywhere else.

Gee, it's almost like there are TWO water columns for that exact purpose!

These water columns are only a few inches away from each other. It may as well just be big single glass of water. The closer we get things to our face in the foreground, the more accurate all leveling needs to be. You are assuming that we can just wing it on the imprecise nature water tension and the fact that the water levels are arguably off very slightly in the images.

None can doubt that a slight error in altitude and leveling in the foreground can create a large impact on the background. You are just winging without knowing how precise you need to be.

The horizon is one of the the furthest thing on earth that can be measured. Don't you think that maybe the requirements with such slight leveling and alignment in the foreground are pretty important?

[Tontogary]

If the water levels in the tubes line up, the camera can't be anywhere else.

Gee, it's almost like there are TWO water columns for that exact purpose!

The horizon is one of the the furthest thing on earth that can be measured. Don't you think that maybe the requirements with such slight leveling and alignment in the foreground are pretty important?

And yet i dont see you suggesting that any of the experiments in EnaG that use plumb bobs and protractors, or levels are in error? You seem to accept all of them as gospel, experiment 15 does, as do many of his other experiments, and that experiment measures the horizon (apparently)
If it is so vital for the experiments to be perfectly level, then why did Rowbotham not detail his method of levelling, the hieght of his experiments, or show exactly what he did to level his “clinometer” he even put the word “levelled” in brackets. I would suggest to show he might have had doubts???

Surely the same level of standards should be applied to Bobbys experiment, as at least he is willing to show how he got his answers, and discuss it, much more than EnaG does.

[Tom Bishop]

And yet i dont see you suggesting that any of the experiments in EnaG that use plumb bobs and protractors, or levels are in error? You seem to accept all of them as gospel, experiment 15 does, as do many of his other experiments, and that experiment measures the horizon (apparently)
If it is so vital for the experiments to be perfectly level, then why did Rowbotham not detail his method of levelling, the hieght of his experiments, or show exactly what he did to level his “clinometer” he even put the word “levelled” in brackets. I would suggest to show he might have had doubts???

Surely the same level of standards should be applied to Bobbys experiment, as at least he is willing to show how he got his answers, and discuss it, much more than EnaG does.

Rowbotham specifically avoids debates about the accuracy of his surveying methods by designing experiments that have two modes: success or fail. Is the object in the distance visible, or is it hidden by the curve of the earth? Simple experiments.

We cannot really take him to task on his surveying methods for that purpose.

[Tontogary]

And yet i dont see you suggesting that any of the experiments in EnaG that use plumb bobs and protractors, or levels are in error? You seem to accept all of them as gospel, experiment 15 does, as do many of his other experiments, and that experiment measures the horizon (apparently)
If it is so vital for the experiments to be perfectly level, then why did Rowbotham not detail his method of levelling, the hieght of his experiments, or show exactly what he did to level his “clinometer” he even put the word “levelled” in brackets. I would suggest to show he might have had doubts???

Surely the same level of standards should be applied to Bobbys experiment, as at least he is willing to show how he got his answers, and discuss it, much more than EnaG does.

Rowbotham specifically avoids debates about the accuracy of his surveying methods by designing experiments that have two modes: success or fail. Is the object in the distance visible, or is it hidden by the curve of the earth? Simple experiments.

We cannot really take him to task on his surveying methods for that purpose.

And his experiment 15?

He looks out of a window with a “clinometer” then runs up a flight of stairs with same object, and measures the horizon, and determines that there is no difference? The whole outcome of this experiment is acutely dependant on his instrument being levelled. And yet we cannot dispute the accuracy of it?

His measurements of the sun from London’s bridge and Brighton are equally false, and have been shown to be vastly inaccurate, but these figures are used to calculate distances of the sun from the earth.

A lot of his experiments are dependant on a level or measurement, and there is not a single explanation on how he does this, experiments 3,4,6,11,14,15, plus many in the later chapters fail if the levelling was not done correctly, or his measurements not accurate. He also relies upon the accounts of writings in newspaper articles as evidence.
I fail to see how all of his experiments are not required to be accurate!

[Tom Bishop]

And yet i dont see you suggesting that any of the experiments in EnaG that use plumb bobs and protractors, or levels are in error? You seem to accept all of them as gospel, experiment 15 does, as do many of his other experiments, and that experiment measures the horizon (apparently)
If it is so vital for the experiments to be perfectly level, then why did Rowbotham not detail his method of levelling, the hieght of his experiments, or show exactly what he did to level his “clinometer” he even put the word “levelled” in brackets. I would suggest to show he might have had doubts???

Surely the same level of standards should be applied to Bobbys experiment, as at least he is willing to show how he got his answers, and discuss it, much more than EnaG does.

Rowbotham specifically avoids debates about the accuracy of his surveying methods by designing experiments that have two modes: success or fail. Is the object in the distance visible, or is it hidden by the curve of the earth? Simple experiments.

We cannot really take him to task on his surveying methods for that purpose.

And his experiment 15?

He looks out of a window with a “clinometer” then runs up a flight of stairs with same object, and measures the horizon, and determines that there is no difference? The whole outcome of this experiment is acutely dependant on his instrument being levelled. And yet we cannot dispute the accuracy of it?

Nothing is stopping you from attacking his ability to level a clinometer. The foundational experiments of Earth Not a Globe are the basic water convexity experiments that simply assess whether bodies are visible or not, however.

[Bobby Shafto]

Rowbotham specifically avoids debates about the accuracy of his surveying methods by designing experiments that have two modes: success or fail. Is the object in the distance visible, or is it hidden by the curve of the earth? Simple experiments.

We cannot really take him to task on his surveying methods for that purpose.

And yet...you are challenging the precision of my method.

It's a pass/fail test. Is the horizon level with the eye or not regardless of elevation? It's what Rowbotham did in Experiment 15. He reported it did. The premise that it does is the basis for several of his other experiments.

Rowbotham simply reported that he saw no declination in horizon from eye level. I'm showing you images, and you've questioned the legitimacy of my images. I don't mind. I welcome the questions, but I also expect a reasoned dialogue about those questions. You've not questioned Rowbotham at all and taken him at his word. Would you do that for me?

I've taken preliminary looks from elevations well higher than the top floor of the Brighton Grand.
I've shown and explained what tools I'm using to detect any dip in horizon from below eye-level. I don't know anything about Rowbotham's tool: what it was, how he leveled it, how he sighted along it's edge. If my method has potential for error margin (which I'm sure it does), then why isn't Rowbotham subject to the same level of skepticism or at least caution in accepting his conclusion carte blanche.

He makes a claim in the book that the sun appears to increase in size as it tends towards sunset. That's contrary to what others in the FE camp say, showing alleged video still evidence of a shrinking sun.  Yet, I've found no such shrink or swelling in the angular diameter of the sun. Rowbotham did nothing other than assert his claim, as if it was self-evident. I've posted pictures of the sun throughout the day, filtered for glare, using a constant focal length and then using the same technique you have for measuring angular dimension in a photo image: pixels. 

Rowbotham isn't an angel, right? Nor a saint? He can be wrong, can't he? His word is not infallible.

I'm not even asking for the same latitude you grant Rowbotham. All I want is good criticism that isn't just gainsaying or unwillingness to see how the critique is answerable. And that whatever zetetic examination you give me, do the same for EnaG. Don't just take Rowbotham's word for his results. Go out and do them yourself. Show us how it's done instead of directing us to the book or saying that Rowbotham already did it, so it doesn't have to be redone. Let's bring his experiments into the modern age. Document his results through replication. Let's get it on the FE favorite medium of YouTube.

[Bobby Shafto]

These water columns are only a few inches away from each other. It may as well just be big single glass of water.

How did RS's clinometer work that makes it more trustworthy to you.

The recommendation was given early in this topic to skip the connect tubes and just use a basin. Fill it to the brim and make your sighting along that. Would that be good? Lets say a shallow receptacle of about 5 inches wide but 36 inches long.

Or, we can ditch the cube since few seem to get why that adds anything to the effort. And just use water tubes at the end of a garden hose. We can stretch that out over many feet (though I don't want to be hauling around that much water). That's the technique many use for finding level points over broad distances, like building a deck. It works. It's just cumbersome and becomes harder to get a good focus on both water levels from a single vantage point. (For leveling, you typically have two people making marks where the water level is.

Come to think of it, that's how to use the hose technique. You plant 2 vertical posts however far apart you want. Then use the hose water level to mark equivalent elevations, attach a cross member of some kind, and then do your eye-level sighting between those two sights. That actually might be the best way to do it if I wind up feeling I need to hike up one of the taller local "mountain" that don't offer me vehicle access. I could even leave it set up and, as long as county officials don't take it down, anyone could use it to inspect the horizon vs. eye-level.

Hmm. 

Anyway, I do acknowledge the issue that a short distance between the 2 level sighting lines increases the margin of error for gauging against another line much, much further away. It's geometric, and you can calculate it. But rather than do that, I'll experiment and show you the range of viewing heights does to the observation, and you can decide if it matters. I have an idea how to do that, so check back in the next couple of days and I'll have something for you.

[Bobby Shafto]

The horizon is one of the the furthest thing on earth that can be measured. Don't you think that maybe the requirements with such slight leveling and alignment in the foreground are pretty important?

Since you mentioned it, how far away IS the horizon? I can't get a handle on what the horizon even is in EnaG.

Seems maybe it's not a single point, but a continuous plane that runs parallel to the eye, and distance along that plane is dependent on how high (or low) other planes are from eye level. If you put jellybeans on the floor and lay down so your eye is level with the jellybeans, how far away is the jellybean horizon? If the sun is on a plane 3000 miles over the earth, how far away is the sun horizon? You know, that variable point where the ground plane stops sloping up and turns horizontal to eye-level:



Frustrates me that this leaves me baffled.

I can calculate a distance to the horizon on a globe earth within some degree of confidence, knowing height of the observer and fudging for refraction. But I have no idea if there's a way to know the distance to the horizon on a flat earth or how it can be the furthest thing on earth that can be measured.

[AATW]

This activity by Bobby has conclusively proved that the world is round.

Appreciate this, but if it's proved anything yet (which I think we're still in the preliminary stage, working out kinks and challenges), it's that the horizon is not always at eye level. Whether or not that kills flat earth, I don't know.

On the other hand, if the horizon was actually always rising to eye level, there's no way the earth surface could be convex. But since we're not seeing that, convexity survives. How flatness could explain a falling horizon with rise in elevation is another story.

I don't think you have proved a round earth directly, but you have certainly proved horizon dip, despite Tom's desperate flailing.
Note how Tom mentioned none of the objections he is now raising when shown the initial experiments.
I can't tell if he's just being stubborn or in "debate club" mode and enjoying trying to keep a debate going when you have killed it stone dead and settled the matter pretty conclusively.

To prove a globe - or provide good evidence for it - you would need to calculate the angle of horizon dip expected on a globe at different altitudes and then show experimentally that the dip angle is as expected. That would give confidence in the model.

[Bobby Shafto]

In trying to demonstrate for Tom how much the camera height needs to change for figuring a margin of error on "eye level," I realize I may be able to do that.

In the meantime, here are 3 stills from the same shot, with the only change being camera height. The top image is camera lower than water level, producing a sighting in which the near tube level appears 1px higher than the far tube level. I can see the misalignment with my eye.

In the middle image, I eyeballed the water to be level, but measuring from the bottom of the meniscus in each tube, the level of the near tube is actually 1px lower than the far tube level. That means the camera is higher than the water level.

In the bottom image, the camera is definitely too high since I can clearly (IMO) see that the near tube water level is lower than the far tube's.

The tubes are about 14" apart and the guideline is equidistant between them.
The camera is set back about 30" from the near tube.
These are un-resized stills from a video clip, and I can't remember what resolution my camera is set to record video in, so I can't yet work out the geometry to see what angular dimension 1px of image is equivalent to. But working that out, I should be able to calculate how much the camera was moved in the vertical axis to generate the differences in the top and bottom images.

The top and bottom images are what I would consider the boundaries for margin of error, and my guess is the camera height was adjusted by about 1" between 1px too low (top image) to 1px too high (middle image).  The third image is 5px too high, and yet the guide string still hasn't reached the apparent horizon, so even with this margin of error, from about 800' in elevation, it doesn't seem to matter in answering a yes/no question of whether or not the horizon is at eye level. Even giving "eye-level the benefit of doubt at the outer range of error margin, there's still a gap.



I hope to reproduce this and actually take measurements of the change in camera height rather than deduce it through calculation, but in the meantime, have a look at the video clip:

Knowing the dimensions of the water leveler/camera setup up, and gauging the amount of camera height adjustment needed to bring the guideline in contact with horizon, we can, in fact, calculate the "dip" from level horizon. What will be missing is a target at a known distance that would be on the tangent point of the assumed globe.

I didn't notice it at the time, but there is a container ship that becomes apparent on the horizon just north of the setting sun. It might be possible to use that if we assume not too much of it's hull is obscured by the horizon (or convergence zone if you prefer) and we can estimate it's size/class.

[Bobby Shafto]

Maybe 800-1000ft long.
35-40ft above the waterline.

Looks like we're seeing it from close to 90degs, (probably heading out from Long Beach). Given how much of it we're seeing, I might very well be close to the distance where a globe earth would predict the visual horizon to be. Might be a fun exercise in geometry/trig to see.

(However far away it is, I'd say it's clearly below "eye level" so a FE model might need to start on a rework of the explanation for the apparent horizon, I would say.)

[Tontogary]

Maybe 800-1000ft long.
35-40ft above the waterline.

Looks like we're seeing it from close to 90degs, (probably heading out from Long Beach). Given how much of it we're seeing, I might very well be close to the distance where a globe earth would predict the visual horizon to be. Might be a fun exercise in geometry/trig to see.

(However far away it is, I'd say it's clearly below "eye level" so a FE model might need to start on a rework of the explanation for the apparent horizon, I would say.)

The horizon form 800 feet up using GE tables gives you a 33.1 nautical mile distance, or 38.1 statute mile distance.

The ship slightly below the horizon is a supertanker, in the region of 330M long, and from waterline to deck will vary between 10m when loaded to about 20M when empty. I think she is half hull over the horizon, or half loaded or a combination of the 2. I also recon you have a pretty good clear horizon there.

I know this because i have worked in those waters, on those ships, and was a captain of the smaller ships that load out there, and have worked in the area where they do ship to ship cargo transfers, which are in that region, and pretty much where you are taking the shots.

Try looking on “marine traffic.com” and see if you can identify it, i realise it might have left, but if it is doing a cargo operation it will hang around for 24 hours or so. If you have a signal on the point where you take the observations you might get lucky and find the name of the ship next time, and from that you can find the course (giving aspect) and length so might be able to use that. If nothing else you might get the distance away it is.

[Tontogary]

Just looked on Marine traffic, and i recon the ship is the “sea passion” 333M long, and she is likely to have been in the area for about 36 hours.

I know this because i can see from your picture she is a large crude carrier, and believe me there are NOT that many inn that part of the world. As i said I have worked on that operation and in that area.

Her AIS data shows she is fully loaded and would have a about 15 metres of hull above the waterline. She will also have instructions to remain a minimum of 25 miles off the coast at the headlands, so it is safe to say she is at least that distance away.

[Bobby Shafto]

This is all too lucky. Now, we do have a target and might be able to calculate a dip below eye level and see if it matches that predicted by spherical earth.

I did rough CAD estimate and figure the length to height (not superstructure) is about 1:21. If you're right about the ship, then we can deduce how much of the hull should be above the water line and, then, how much (if any) is obscured by horizon.

[Bobby Shafto]

Another gauge might be the sun itself. At the horizon, it is filtered enough by the marine layer that you can see it's truer size, and at 32 arcminutes, the sun would give us a ruler of sorts to use for the ship.

[Tontogary]

The sun would be a much better measure, as it will give you the dip in arc minutes, and i can tell you what that is supposed to be.

The semi diameter of the sun will be 15.8 arc minutes, or 31.6 across the diameter. You can get this info from nautical tables.

I would not use the vertical measurement as the refraction affects this, however horizontal measurement is pretty good.

The fact that you measured it at 32 arc minutes is verified as pretty close, as the semi diameter is published and known.

[MCToon]

Bobby, you have performed a pass/fail experiment as EnaG claims to do:

Pass: Horizon is visibly on the same plane as the water in the tubes
Fail: Horizon is visibly not on the same plane as the water in the tubes

I've read experiment #15.  In this thread you have provided more documentation and rigor than shown in the book.  Tom is simply refusing to accept the results.  He doesn't seem to want to answer my question about vertically centering the image.  I'll ask again:
"Tom, if the camera is vertically centered and you can count the same number of pixels above and below the line would you accept this as a valid experiment and acknowledge the results?"

If your answer is "no", then what are your requirements to perform this experiment?  What equipment did you use when you verified the horizon rises to eye level claims in EnaG?

[9 out of 10 doctors agree]

Just looked on Marine traffic, and i recon the ship is the “sea passion” 333M long, and she is likely to have been in the area for about 36 hours.

I know this because i can see from your picture she is a large crude carrier, and believe me there are NOT that many in that part of the world. As i said I have worked on that operation and in that area.

Her AIS data shows she is fully loaded and would have a about 15 metres of hull above the waterline. She will also have instructions to remain a minimum of 25 miles off the coast at the headlands, so it is safe to say she is at least that distance away.

What is her mast height? Bobby seems to be measuring it from that.

[Max_Almond]

Here are six simple ways for measuring whether the horizon is at eye level or not:

1. Use a professional theodolite. Eye level is where the crosshair is:



2. Download and properly calibrate a theodolite app. Eye level is where the crosshair is:



3. Make your own theodolite using a spirit level. Eye level is level with the top of the spirit level, when you're sighting along it:



www.metabunk.org/posts/204999

4. Use parallel lines to find the vanishing point (which is always at eye level):



5. Take a picture of some actual eyes, with the camera at eye height, and see where the horizon is:



6. Use a homemade water level. Eye level is where the surfaces of the water are aligned:

[Bobby Shafto]

This is an annotated 1920x1080 resolution image taken as sunset
on 5/15/2017 at 19:41 PDT
from La Jolla's Mt Soledad
32.840319
-117.245065
approx. 790' MSL
on an azimuth of ~294° true