Lake Balaton Laser experiment to determine the curvature of the Earth, if any.

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The important thing is here that Sandor does fully understand the method and to my knowledge he followed it accurately and Mick has confirmed this.

Nope. I saw where Sandor (in posts here)seemed to think that "slope correction" has something to do with physically leveling the laser and Mick has commented that Sandor seems to be applying the term in a different manner to what he had suggested.
 
Nope. I saw where Sandor (in posts here)seemed to think that "slope correction" has something to do with physically leveling the laser and Mick has commented that Sandor seems to be applying the term in a different manner to what he had suggested.

Yes, but Sandor seems to understand the issues with the slope of the laser, regardless of the terms he used.

As I said though, it's basically irrelevant. You need a series of accurate measurements to see if there is a curve. They did not get this.
 
Sorry this is so long...

It was certainly not my intention to paraphrase, it was my honest belief that you said leveling method would be accurate if they took enough measurements. Please feel free to correct me publicly. I don't really want to go searching for the quote.

They have to be accurate measurements -- what was agreed to was measuring a laser spot on a board -- "direct hit in camera" was never discussed. And we had strong objections that the laser spot would be as accurate as claimed (and we were correct). Camera 'hits' is not a valid measurement, nor are measurements from a moving boat. You need to stop the boat, make sure everyone is in exactly the same place in the boat for the measurement (if people are moving around you are tilting the boat), let the boat stabilize, and observe the minimum and maximum 'bob' on the board so you can find the average -- and even then your margin of error is going to be very large. We've repeatedly said not to do this and it was ignored -- since @Sandor Szekely & team insisted on using the boat method we've simply tried to accommodate this as best we could.

But if the data is collected carelessly then the results are useless.

There have been a lot of sweeping statements about the method of the experiment being flawed and badly conducted. What is your opinion as to the method they undertook? Did they follow your method? Was it conducted poorly? Did they take on board suggestions put forward in this forum or ignore them?

Very flawed and they haven't shared their measurements here for review yet which is very suspect. And we reject the "direct hit" in the camera claim until it can be established to be accurate. It's not OUR job to prove their methods are reliable for them. We can discuss it -- and we have -- but then you and they ignore us. Here I'll state it again: Camera "hits" are not reliable.


Here are some quotes from this thread - just to collect them into one place.

Mick's very first post on this thread, which was mostly ignored:

A) you still used the boat method
B) the laser was placed close to the water
C) -- Mick was incorrect about this but it would have been avoided if B was followed
D) no middle target at a known, fixed height

A more accurate way of performing this experiment would be to

A) have all the elements on the ground.
B) have the laser as high as possible to reduce refraction effects
C) perform the test at dawn, to reduce refraction effects.
D) have a middle target between the laser and the longest range target

It should not really have to be that long a distance either. Three miles will result in a horizontal laser beam being six feet higher (as demonstrated on Hawkins Genius).

The difficulty is getting the laser beam horizontal. If you are out by 1" at 20 feet, then at three miles (15840 feet) then the error then becomes 66 feet.

To reduce the error to a reasonable 1 foot, you need an accuracy at 20 feet of 1/66th of an inch (0.38mm). Since you clearly don't have that on your bobbing boat, the results are irrelevant and prove nothing.

However, if you have a middle target, and everything on the ground, then you can measure the height of the beam at both points, and eliminate any calibration error (it likely won't be perfectly horizontal, but you can do the math from this to demonstrate the curve, assuming the laser beam is narrow enough to measure)

For example:
20160731-083301-qva3t.jpg

Did @Sandor Szekely & team go back to the start and take interval measurements?

Calibrate it at 2KM if you like, but then come back to the start, and take your reading from there. It's very important to have a constant value of L (the tilt of the laser) over the entire journey.

@Sandor Szekely and team did go with option B here -- but seem to be almost 50% off their mark (should have been +4cm was at +7cm), which is fine but let's not pretend the laser was perfectly leveled. We have ONE questionable data point from a moving boat.

B) If you think the Earth is round, then you'd adjust it to 1.6 + 0.66 = 2.26 feet, and this will give you a perfectly horizontal laser, and the clearest results. However if the Earth is flat, then this will make the laser rise up with distance, linearly.

I again encouraged @Sandor Szekely & team to use the Wallace method which he seemed open to doing -- but then you didn't.

I am ready to make measurement dedicated to Metabunk ideas :) on the experiment day, especially at daytime when our laser will not be well seen on long distance.

And his rationale is fine -- I'm not opposed to the current experiment but our suggestions did get tossed under the boat, so to speak:

The main reasons for the boat is the laser beam height measurement on the complete distance. We can set many points to define the line of the laser beam and also to have reference points for the refraction arguments.

I think this sums up what we're looking for in that case -- but it DEPENDS on accurate measurement.

This is VERY IMPORTANT:
Mick : "You just need to show that the measurements do not lay on a straight line."

Exactly! And in my opinion my type of slope corrected level measurement will give a more definite result than the Wallace type measurement. I am ready to do both, and I can find a target in position B to level the laser as Wallace did.

Important note that was ignored - we touch on this repeatedly.

#2 Wallace avoided the worst of the refraction by shooting 13 feet up instead of 8 inches above the water. When you take the observation also matters.

For example:

That said. I do not believe that, at ~21km, you can hit a target that is only 3 meters above the water level from 3 meters up. I think you would need to be about 9 meters up to hit a 9 meter high target at 21km -- maybe 8m/8m with refraction (varies with conditions -- if you hit a thermal duct you could make it further of course). So you might want to have a plan in place for that (some positions up a little higher). Maybe have a camera with a good optical zoom taking a timelapse of the distance shore so we can at least see changes in the refraction index?

Whatever else, PLEASE keep things up off the water level or that will spoil it due to refraction concerns.

As for specific numbers, at 21.5km the sagitta ('Bulge' Height) should be approx 9.1 meters. Which means you need to be 9.1 meters up to hit a 9.1 meter high target (before accounting for refraction) and you use https://www.metabunk.org/curve/ to figure out whatever specifics you have and figure *about* +1/7 Earth curvature for nominal refraction.

In the interest of full disclosure Mick did say this - which I strongly disagree with :) I would suggest at least 5-10 meters over the water...

  • Use a concrete jetty, or similar, with a level surface, a few feet above the water (exact height is not important)

Another concern that was ignored was the collimation. Here is the claim:

this is a masterpiece! a 0.03 mRad collimator lens set designed for this experiment!
that is 0.03 milli radius :)

we will have a laser beam divergence of 3.9xx inch (about 10 cms) at the 14.3 miles (23kms) distance!
I think that is a pretty awsome divergence - not? :)

0.03 mrad really WOULD be amazing... But we have very serious concerns about the methodology here -- both in terms of the claimed laser collimation (which is just impossible) and in the use of "direct hit" to camera.

This was never discussed or agreed to and seems extremely suspect. It is up to @Sandor Szekely & team to establish the reliability of their methods.

Unless @Sandor Szekely can accept that there are problems in the methodology I suspect we're just going to disagree and they will make their video and proclaim ABSOLUTE VICTORY -- while ignoring all the problems and all the contradictory data.

But the further claim made was just ridiculous:

SORRY, I wanted to say 0.003 mRad collimator lenses. this EXACT data will be given to us be the laserist when they calibrated the new collimator lens set unit.

Which was pointed out as IMPOSSIBLE and beyond even theoretical limits.

I think your laserist is lying to you.

Content from external source
There is a fundamental limit to the collimation of a laser due to diffraction. Assuming the laser beam profile is a uniform disk it will be diffracted to an Airy disk at large distances, and the angular spread is approximately given by:


θ≈1.22λdθ1.22λd


where dd is the beam diameter. Assuming a diameter of 1 mm, which seems a reasonable estimate for most lasers I've seen, you get an angular divergence of about 0.6 milliradians for 500nm light.


The theoretical MINIMUM divergence with a PERFECT lens is: θ = (4*λ) / (π*beam diameter)

The collimated Beam diameter is approximately between 4 and 5cm (I'll be generous and say 6cm, wider is better), Green light λ (wavelength) is 560–520mm (I'll be generous and say 520nm, shorter wavelength is better, so we get a MINIMUM value)

http://www.wolframalpha.com/input/?i=(4*520nm)/(π*6cm)+radians = 0.01103 mrad (milliradians)

So there is NO WAY you got 0.003 mrad, not even in THEORY, and I think the results shown by the amount of spread evident at just 700 meters which is already about 25cm, prove this out -- that suggests your actual value is 0.35 mrad. That's ~116 times the claimed value. Not even in the ballpark.

So that puts us at 209 cm wide at 6km (Angular size at some distance is given by g = 2*d*tan(α/2)). So getting 'direct hits' in the camera at some small distance over the white board would tell us nothing.

CORRECTION: as noted in a following post, only 1/2 this beam spread width is "below the center line" so cut that 209cm in half.

Indeed, this amount of spread would wipe out 2 meters curvature at 6km. That's puts us at:

Round Earth Slope

Let's say that over 700m we went from 125cm to 132cm - that's 7cm, 4cm of which would be curvature 'drop' so that leaves 3cm per 700m or just about 26cm over 6km for the rise due to angle above level.

So at 6km (before diffraction and refraction) we would expect the laser to be 283cm + 26cm = 309cm above the 125cm level.

(R1) slope = 3cm/700m
(R2) slope offset at 6km = 26cm
(R3) total rise at 6km = 309cm

309cm - 209cm = 100cm -- so now you are only about 1 meter above the 125 cm mark on the board.

CORRECTION: since it's 1/2 the beam spread width below the center line that should be 204.5cm above the 125cm mark on the board.


Mick -- please check my math and assumptions!! I'm on cold medication today so feeling fuzzy but I triple checked it and I think it's good.
 
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C) [perform the test at dawn, to reduce refraction effects.]-- Mick was incorrect about this but it would have been avoided if B was followed

I just want to clarify this. The idea is that you do it when the air and the water are the same temperature. I was incorrect because I was assuming the lake would be cold, and so you'd want to do the experiment when the air was cold. I based this on my personal experience with large bodies of water, namely the Pacific, and specifically at Santa Monica, California, where the water temperature is around 60-65°F in summer, about the same as the overnight low.

The point here for similar experiments is that the best time to do the experiment will vary depending on your location, the time of year, and the weather. There is no rule of thumb here.
 
Please explain,
1. If the laser was angled downwards, what evidence do you have for that?
2. If the beam was refracted downwards, as apposed to the clearly observed upwards refraction that has been so heavily discussed inthis forum, what evidence do you have for that?
3. If the beam had a wide divergence at the time when they took the readings that made thereadings inaccurate, what evidence do you have for that?

(1) This was my misunderstanding that the 125cm mark was at 717m out -- it was clarified that the ~132cm giant laser spot was at 717m so that means the beam is pointing slightly up -- I've since posted a detailed analysis of that including the exact calculations. So you can drop (1) but should review my later analysis: https://www.metabunk.org/lake-balat...of-the-earth-if-any.t7780/page-10#post-188913

(2) refraction exists -- we SEE it clearly in the photos @Sandor Szekely provided. Neither of know exactly how much it affected THESE specific measurements but it simply must be accounted for. Period.

This kind of stuff is where you verge towards being purposefully disingenuous. Let's not do that. Let's try to find out exactly what the observations are and discuss what they can tell us.

(3) First and foremost we OBSERVE the fairly large beam divergence in the 717m photo, it's already about 25cm wide. (see previous discussion for details). That puts it at about 209cm wide at 6km.

But also, beam divergence IS A HARD PHYSICAL LIMIT. You'd have to prove you can do better than labs funded with millions of dollars and top end equipment and professionals that know what they are doing. See my previous comment where I cover this in great detail. We had also previously discussed this in the thread prior to the 'experiment' and I cited that discussion as well in my previous comment.

And again -- we don't have to prove their methods are reliable, they have to demonstrate their reliability.

We are willing to assume the well-established fundamentals without a repeated demonstration (things like your meter stick is close enough to a meter for this purpose) and there are probably a million such things we're taking on your good word -- we're just pointing out the most egregious and contested points and we have to discuss those openly and in good faith. Don't you agree?

(1) Do you not see how taking measurements in a moving boat is a problem?

(2) Do you not agree that laser beams diverge and it's impossible to prevent this even with perfect optics?

(3) Do you disagree that we see about 25cm of divergence in the 717m photo?
 
I just want to clarify this. The idea is that you do it when the air and the water are the same temperature. I was incorrect because I was assuming the lake would be cold, and so you'd want to do the experiment when the air was cold. I based this on my personal experience with large bodies of water, namely the Pacific, and specifically at Santa Monica, California, where the water temperature is around 60-65°F in summer, about the same as the overnight low.

The point here for similar experiments is that the best time to do the experiment will vary depending on your location, the time of year, and the weather. There is no rule of thumb here.

I tentatively agree that when water and air temps are similar would be the best time, but I'm not an atmospheric scientist either. We also have to worry about water vapor and pressure gradients. Any experiment like this is going to have to contend with refraction - even if you raise the laser/observer altitude -- but our best understanding is that the higher the altitude the lower the amount of refraction there should be (and less variance).

And, of course, no judgement was implied (I just meant it turned out that wasn't a good time). BTW: I agreed with you at the time that this would be better than the evening so I didn't object - I was wrong also. Such errors are a normal part of the process - that's why we want to collectively look at the available information. The key is how we proceed once there is a disagreement. This is where proper understanding is key.


So the process is:

1) do our best to understand what is known about optical/atmospheric phenomena
2) make some predictions based on the model, as we understand it
3) make some observations and compare them to our model
4) when we collectively disagree or observation disagrees with our collective prediction, we know we missed something and try to account for it (e.g., we learned that water vapor is less dense than air)
5) and remember that disagreement rules out your model to the extent that the measurements are accurate -- but MERE agreement doesn't necessarily confirm your model (your measurements can be inaccurate giving only the appearance of agreement and your model can be 'right' for the wrong reasons). For example the laser could measure as 'flat' but it could turn out refraction is the culprit. This is a known actual possibility and must be accounted for. We also have the beam spread issue, which appears to be a significant concern at this point.

Looks good to me.

Unfortunately, we both missed something critical -- I gave the TOTAL angular spread, not 1/2 spread. So cut that in half as we are only concerned with the half below the center line.

I would hope that @Sandor Szekely & team would comment on the beam spread at least:

I think the results shown by the amount of spread evident at just 700 meters which is already about 25cm, prove this out -- that suggests your actual value is 0.35 mrad. That's ~116 times the claimed value. Not even in the ballpark.

So that puts us at 209 cm wide at 6km (Angular size at some distance is given by g = 2*d*tan(α/2)). So getting 'direct hits' in the camera at some small distance over the white board would tell us nothing.

Indeed, this amount of spread would wipe out 2 meters curvature at 6km. That's puts us at:

309cm - 209cm = 100cm -- so now you are only about 1 meter above the 125 cm mark on the board.

With my correction above, using 1/2 the observed divergence, that moves it to:

309cm - 104.5cm = 204.5cm

If that is the case then Flat = +60cm and Curved = +204.5cm (above the 125cm mark)

And again, the math and methodology, is open to criticism & correction here - but please don't try to deny that the laser beam had already spread significantly at only ~717m out. The extents are clearly visible at about 35cm wide, I used 25cm to be conservative. It doesn't matter what is causing this divergence, that is what you observed.

I don't even like to extrapolate it from here but it isn't going to get *better* with distance (but it could be worse) -- @Sandor Szekely should provide direct observations of it at distance, so we can all come to an agreement on what it was at 6km out. I look forward to clear visual evidence of the beam spread on a target at greater distances.
20160816_064208 LEVELING 1-spread-25cm.jpg


As a reminder, here is my diagram showing what the observations (so far) seem to support:
LakeBalatonLaserDiagram.png
 
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Nope. I saw where Sandor (in posts here)seemed to think that "slope correction" has something to do with physically leveling the laser and Mick has commented that Sandor seems to be applying the term in a different manner to what he had suggested.

I suggest we let this be water under the bridge.

:rolleyes:
 
Quick 2 cents here, @Sandor Szekely .

The "Hawkins experiment" was highly criticized by you because the measurements were not accurate and it looked amateurish.

Although your setup is not amateurish at all, the measurement method chose by you and your team was to rely on a "direct hit" and "estimated camera height", what is even worse than the one chosen in the Hawkins experiment.

I think the setup you have is good, but the measurement's part need to be rethought and re-planned, and unfortunately the experiment need to be re-executed with the new strategy.

Science is all about enhancing your process if your initial process was inconclusive, what I suppose you realize happened. Some experiments take dozens of enhancement rounds before perfection is achieved. It's not about proving a point (globe or flat), it's about executing the experiment the right way to gather the correct data. Analysis and conclusions are only the last steps.
 
Quick 2 cents here, @Sandor Szekely .

The "Hawkins experiment" was highly criticized by you because the measurements were not accurate and it looked amateurish.

Although your setup is not amateurish at all, the measurement method chose by you and your team was to rely on a "direct hit" and "estimated camera height", what is even worse than the one chosen in the Hawkins experiment.

Nice & succinct - spot on. I don't think Hawking team lied but I think a lot of the (important) but technical details got cut out. Maybe we should write to them and see if we can get any details.

Science is all about enhancing your process if your initial process was inconclusive, what I suppose you realize happened.

We can hope but I have little doubt the video will just proclaim "Earth IS Flat! 100% PROOF" and we will all move on. Can already see this in the various posts. Too bad if that happens - will be business as usual.



But hey, I found a really short & simple geometrical argument earlier today...

To a fairly high degree of accuracy (for the sake of argument let's say only within +/- ONE THOUSAND kilometers), the distance from North Pole to Equator is known to be 10,002 km and the equatorial radius is 40,075 km.

By simple geometry we know that a circle with a radius of 10,002 km would have a circumference in the range of 62,844.4 km -- That is IMPOSSIBLY too Large for Earth. Even if you think that π is 3, that STILL makes it 60,012 km around.

Conversely, a circle with a circumference of 40,075 km would have a radius of just 6,378.13 km -- IMPOSSIBLY too Small for Earth. Therefore the Earth simply cannot be flat if these measurements are anywhere even close to the observed values.

You simply cannot make these observations fit.
 
Very flawed and they haven't shared their measurements here for review yet which is very suspect.

This is exactly the kind of sweeping statement I'm talking about. How can you say it's very flawed and in the same breath say that data hasn't been submitted yet? What are you basing that statement on exactly? Why is it suspect? Is it not possible that they are just being careful to present the information accurately and are taking their time to make sure it's done properly? Why are you presupposing failure based on such a small amount of submitted data?

This kind of stuff is where you verge towards being purposefully disingenuous.

Is it possible to be disingenuous by asking questions? I feel like you're being disingenuous by giving answers without actually answering my questions. I know that refraction exists and that we observe it, the problem is that we only observerd upwards refraction and the evidence shows that the laser was pointed up slightly, am I right? Just because you've seen a couple of photos of wide beam divergence doesn't mean the experiment was a failure, because as I said (which you chose to ignore) the wide beam divergence was an anomaly that was observed intermittently.

My points again, which seem to be getting ignored are:
1. Laser levelling, is the laser level?
2. Refraction, we seem to observe only upwards refraction.
3. Beam divergence, we have observed wide beam divergence but it was an intermittent phenomenon, narrow beam divergence over long distances was also observed.

If we could assume for a moment that the laser was pointed upwards, the refraction was always upwards and the beam divergence was good, how would you explain the readings they got? (ignoring for the moment that the direct hit readings are not accepted as accurate).
 
This is exactly the kind of sweeping statement I'm talking about. How can you say it's very flawed and in the same breath say that data hasn't been submitted yet? What are you basing that statement on exactly? Why is it suspect? Is it not possible that they are just being careful to present the information accurately and are taking their time to make sure it's done properly? Why are you presupposing failure based on such a small amount of submitted data?

IMHO because the data they have released shows fundemental flaws.

they set-up there board at the initial set-up with he laser right at the top knowing that the experiment they where trying to replicate had a 6ft+ movement upwards of the laser so they should have had at least that in both directions just to be safe

they said that they "estimated camera height" you can not call that good data. how and what did they estimate?

they said that they had no beam spread when the photos we have shows considerable spread.

these things we do know and these things show flaws.
 
My points again, which seem to be getting ignored are:
1. Laser levelling, is the laser level?
2. Refraction, we seem to observe only upwards refraction.
3. Beam divergence, we have observed wide beam divergence but it was an intermittent phenomenon, narrow beam divergence over long distances was also observed.

No one has ignored your points/questions. Numerous people have answered/commented on them.

Point 1.
This whole "leveling" and "slope correction" thing is basically irrelevant. You just need a series of accurate height measurements at regular intervals up to a sufficient distance. It's good if you can get the laser so it's not pointing down. When you have the measurements you can work out the slope of the laser and the curve of the earth.

Point 2.
refraction exists -- we SEE it clearly in the photos @Sandor Szekely provided. Neither of know exactly how much it affected THESE specific measurements but it simply must be accounted for. Period.

Point 3.
Some illustration of the issues:
20160823-112916-shpi6.jpg

And if that counts as a "direct hit", then the effective spread of the laser is at least 50% more

Lets look at a hypothetical scenario;

I set up an account on the fictitious "globunk.org" website (possibly hosted by Sandor), present a pre-test video I've uploaded to YouTube that is to prove the curvature of the earth and that it is indeed not flat. My video does not show anything conclusive but a discussion ensues about the best way perform the actual test to minimize flaws and errors. I go off and perform my experiments over two days and collect lots of video/photos and take measurements.

Then I send Sandor a percentage of the photos and video, only he can't access the video, and I also give him a dozen or so measurements, with the intention of including the "globunk" group in my evaluation. I now go off to make a video, while telling Mick what I'm going to put in presentation video, but not telling anyone else. In the meantime, what I've sent to Sandor shows a multitude of errors and general flaws with my methods. I never really address these issues but insist that I finish my video, my way.

Would you be skeptical of what I was doing? Would you not prefer that I allow my fellow evaluators access to all the data, and include them in the process so the correct conclusions can be arrived at?
 
This is exactly the kind of sweeping statement I'm talking about. How can you say it's very flawed and in the same breath say that data hasn't been submitted yet? What are you basing that statement on exactly? Why is it suspect? Is it not possible that they are just being careful to present the information accurately and are taking their time to make sure it's done properly? Why are you presupposing failure based on such a small amount of submitted data?



Is it possible to be disingenuous by asking questions? I feel like you're being disingenuous by giving answers without actually answering my questions. I know that refraction exists and that we observe it, the problem is that we only observerd upwards refraction and the evidence shows that the laser was pointed up slightly, am I right? Just because you've seen a couple of photos of wide beam divergence doesn't mean the experiment was a failure, because as I said (which you chose to ignore) the wide beam divergence was an anomaly that was observed intermittently.

My points again, which seem to be getting ignored are:
1. Laser levelling, is the laser level?
2. Refraction, we seem to observe only upwards refraction.
3. Beam divergence, we have observed wide beam divergence but it was an intermittent phenomenon, narrow beam divergence over long distances was also observed.

If we could assume for a moment that the laser was pointed upwards, the refraction was always upwards and the beam divergence was good, how would you explain the readings they got? (ignoring for the moment that the direct hit readings are not accepted as accurate).
Your points weren't ignored, several members responded to them.

Regarding 'upwards refraction', I still think you're referring to the wrong test - the nighttime one - please see Sandor's comment in post #326.

It's important you're clear on that, because that's one of the key flaws that people are trying to explain to you - they lost the ability to take anything resembling an accurate measurement very early in the test, and that includes measurements of how much the beam diverged/refracted.

Ray Von
 
Dr. Andrew Young has a website about atmospheric optics. http://aty.sdsu.edu/~aty/glossary.html#gradient

I asked him to look at this thread. He was kind enough to send me this email in response:


First of all, I see some discussion of the shape of the geoid.
Deviations from sphericity are interesting, but are probably so small
that they will not show up in such simple experiments. If you want info
on the geoid, the NOAA website has lots of good stuff:

http://www.ngs.noaa.gov/GEOID/geoid_def.html

For directions and ranges on the ellipsoid, see

http://www.ngs.noaa.gov/cgi-bin/Inv_Fwd/inverse2.prl



Regarding the issue of how far you can see, I have some info at the end
of my page

http://aty.sdsu.edu/explain/atmos_refr/horizon.html

that points out that surveyors have actually used baselines as long as
192 miles -- between elevated sites, of course.


Regarding "compensating for" refraction: There's no realistic way to do
this. You'd need temperature data at least an order of magnitude more
accurate than air temperatures can be measured, especially under field
conditions. Aspirated thermometers claim an accuracy of about 0.1
degree; but remember it is the vertical temperature *gradient* that you
need. So you have to construct a very accurate temperature profile.

For this reason, the optical people have repeatedly pointed out that the
sensible way to go is the other direction: use the observed ray bending
to infer the temperature profile. The meteorologists have shown no
interest in this idea, mostly because conditions clear enough to allow
it to be used are relatively uncommon.

Please note that humidity is a small contributor to the refractivity of
air at *optical* wavelengths; so unless the laser was in the IR, you can
(to a good approximation) ignore humidity effects. See my page on the
refractivity of air:

http://aty.sdsu.edu/explain/atmos_refr/air_refr.html

The remark

"However, if the surface of the lake is flat, and the laser
is level, then why would there be any refraction? Vertical
refraction of a straight and level laser over water will
only occur because the water surface, and hence the
temperature gradient above it, is curved. Hence this
demonstration suggests the surface of the lake is curved."

makes no sense to me. Refraction depends on the density gradient of the
air, regardless of the shape of the lake surface. The density gradient
depends on both the temperature gradient and the vertical pressure
gradient due to hydrostatic equilibrium; see my page

http://aty.sdsu.edu/explain/atmos_refr/bending.html

for how to calculate ray bending.


Most people are quite unaware of how much the ray bending varies with
the local meteorological situation. There are well-known diurnal
effects, first noticed in 1674:

http://aty.sdsu.edu/bibliog/bibliog.html#Perrault1967a

-- Perrault's observations showed effects of about a quarter of a degree
on a 2 km path. So of course they are quite visible to the naked eye,
if you have a fixed eye position and a fixed reference point 50 or 100
meters away, and watch the diurnal motion (and the day-to-day motion,
which is considerably larger) of a landmark a few km away.

So, although the "standard" refraction can be computed from a standard
atmospheric model, the real atmosphere -- especially over a body of
water! -- is always different. Sometimes the ray is concave toward the
surface of the Earth; sometimes it is convex. These one-shot experiments
are useless for determining the shape of the Earth.

The nice night-time picture of the laser beam and the lights on the far
shore very clearly miraged (by an inferior mirage) is correctly
described by the lines

"It shows the laser bending upwards, and it looks like it does
actually hit something on the other side. What is fascinating is
that the return light is then split in two, and we get a
"reflection" underneath it, just just like with the lights on
the right."

However, the next line:

" Here it is with some reference lines. The red lines show better
where it actually would be without refraction."

is not true, unless the Earth is flat. The curvature of the Earth makes
the inferior mirage shrink vertically as the height of the eye above
the surface increases. This was first pointed out by Bravais in 1853
(see the reference to his paper in Ann. Met., in the bibliography I
cited above). Unfortunately, because of the complicated path of the
rays in the inferior mirage [see my paper in Appl. Opt. 54, no. 4,
pp. B170-B176 (Feb. 1,2015)], the "reflection" near the surface in the
inferior mirage is not at all like a simple reflection at a solid surface;
so it is not possible to infer the shape of the Earth from this effect.

Anyway, I was glad to see that someone had put "reflection" in quotes,
as it certainly is not a simple reflection at all. Remember that the
temperature profile in the inferior mirage is a logarithmic one (again,
see my Applied Optics paper for the details.)

I don't have time to wade through the rest of this thread, but maybe I
have pointed out where you can find information about these things.

By the way, there are much better time-lapse movies of mirages and
varying refraction during the day on YouTube than the one in this
discussion. Here's one:

https://www.youtube.com/watch?v=AJc3kOxiV6c
Content from External Source
 
Dr Young was quoting this:

13903168_10153671143616671_765952242529684575_n.jpg
This image claims to show the laser beam bending upwards in the distance. This could occur with warm water and cold air, the same as in inferior mirage.



However, if the surface of the lake is flat, and the laser is level, then why would there be any refraction? Vertical refraction of a straight and level laser over water will only occur because the water surface, and hence the temperature gradient above it, is curved. Hence this demonstration suggests the surface of the lake is curved.

And This:

Sandor sent me this photo, camera time 5:00AM taken from a few feet west of the laser
20160819-132417-ydcz3.jpg


It shows the laser bending upwards, and it looks like it does actually hit something on the other side. What is fascinating is that the return light is then split in two, and we get a "reflection" underneath it, just just like with the lights on the right.

Here it is with some reference lines. The red lines show better where it actually would be without refraction.
20160819-132827-b0j35.jpg

From a different angle:
20160819-133455-6672h.jpg
 
Dr. Andrew Young has a website about atmospheric optics. http://aty.sdsu.edu/~aty/glossary.html#gradient

I asked him to look at this thread. He was kind enough to respond.
That's so cool you did this, and triply cool that he responded so thoroughly. I'd been thinking the same thing: that what we need is someone who really knows about refraction - the professional opinion.

So much good information in there. And I guess the key, concluding line is, "one shot experiments like this are useless in determining the shape of the earth" - which obviously covers any shape one wishes it to be, and prove.
 
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Mick had a rare 'brain-fart'.

Not really.

In the first case I was saying there would not be refraction along the path of a level laser. There would be refraction above and below. This does make the assumption that the pressure, temperature, and humidity gradients are vertical, but I don't think that's what Dr. Young was referring to - he's saying there would still be a mirage effect, which is true. But the level plane above level water with purely vertical gradients in the air would have the same refractive index, so if you shoot a laser parallel to the plane, it would not be refracted.

It's important here because if an upwards rise in the beam it to be attributed to "refraction" then one needs to be able to at least roughly describe the gradients that are responsible. This is reasonably straightforward for a curved lake surface, or a beam that goes up or down - vertical gradients work fine. However for a Flat Earth scenario, with a precisely leveled laser, then you need a non-vertical gradient. It seems very unlikely that such a vertical gradient would produce the perfectly flat "layers" of the typical mirages we see here.

And in the second case, I said: "The red lines show better where it actually would be without refraction." And I think that's still true. By "it" I refer to the actual path of the laser, perhaps Dr. Young inferred something else. The vertical red line is accurate, and the horizontal red line shows the path of the laser if it continues without curvature (i.e without atmospheric refraction). I contend that if the atmosphere was removed then the intersection of the red lines would be a better match for the endpoint than either the upper or lower ("reflected") termination spots of the laser.
 
Not really.

In the first case I was saying there would not be refraction along the path of a level laser. There would be refraction above and below. This does make the assumption that the pressure, temperature, and humidity gradients are vertical, but I don't think that's what Dr. Young was referring to - he's saying there would still be a mirage effect, which is true. But the level plane above level water with purely vertical gradients in the air would have the same refractive index, so if you shoot a laser parallel to the plane, it would not be refracted.

It's important here because if an upwards rise in the beam it to be attributed to "refraction" then one needs to be able to at least roughly describe the gradients that are responsible. This is reasonably straightforward for a curved lake surface, or a beam that goes up or down - vertical gradients work fine. However for a Flat Earth scenario, with a precisely leveled laser, then you need a non-vertical gradient. It seems very unlikely that such a vertical gradient would produce the perfectly flat "layers" of the typical mirages we see here.

And in the second case, I said: "The red lines show better where it actually would be without refraction." And I think that's still true. By "it" I refer to the actual path of the laser, perhaps Dr. Young inferred something else. The vertical red line is accurate, and the horizontal red line shows the path of the laser if it continues without curvature (i.e without atmospheric refraction). I contend that if the atmosphere was removed then the intersection of the red lines would be a better match for the endpoint than either the upper or lower ("reflected") termination spots of the laser.

I think this is analogous to a flat earth:
Source: https://www.youtube.com/watch?v=zTx7UoPXvr4
 
I have a question for @Sandor Szekely.

Have you already reached your conclusion from the data you have available to you?

If you have I have a couple other questions.

Are you going to assert that conclusion in your video presentation? Can you tell us what your conclusion is?

If you answered yes to the first question, and intend to assert it without telling us what it is, I see no point to this thread anymore. It would be better to start a new thread once your video has been done.
 
... I don't think Hawking team lied but I think a lot of the (important) but technical details got cut out ...
I never said that his team lied to be clear :)

I talked about how that experiment's standards were criticized and how the new experiment's measurements standards are even less reliable than Hawkins' one.
 
I think the beam there is never perfectly horizontal (in the tank), and variations across the tank (more was poured in the middle) means the layers are not perfectly flat. It does get close to no refraction here (3:10)

20160826-090714-ho32w.jpg

Low refractive index _gradient_ due to it being in the mainly the saturated solution?
 
Low refractive index _gradient_ due to it being in the mainly the saturated solution?

Would a gradient across the beam, and exactly perpendicular to the beam, cause that beam to bend?

Say you've got a 2" wide laser beam, and you have a 1" slab of glass, and another of a different glass with a higher refractive index. Place one slab on the other, shine the beam so it goes through the slabs from the side, parallel to the larger surfaces, perpendicular to the edges.

Is there a bending of the beam there?
20160826-113733-i06ay.jpg (Image create with Ray Optics app in Chrome)

Now this is just with theoretical classical optics, and everything mathematically perfect. Does it change if there's a refractive index gradient rather than a discontinuity? What other effects would make the beam bend?
 
Would a gradient across the beam, and exactly perpendicular to the beam, cause that beam to bend?

Say you've got a 2" wide laser beam, and you have a 1" slab of glass, and another of a different glass with a higher refractive index. Place one slab on the other, shine the beam so it goes through the slabs from the side, parallel to the larger surfaces, perpendicular to the edges.

Is there a bending of the beam there?
20160826-113733-i06ay.jpg (Image create with Ray Optics app in Chrome)

Now this is just with theoretical classical optics, and everything mathematically perfect. Does it change if there's a refractive index gradient rather than a discontinuity? What other effects would make the beam bend?

I am not the best person to ask.. I imagine you will get some edge effects, but the main thing is that there will be a delay though one layer relative to the other. If that delay is a small fraction of a wavelength then when the two paths combine at some large distance there will be a _tiny_ offset in the position of maximum brigtness. For large delays and glass thickness (in term of wavelength) you would get a very fine-structured and messy interference pattern, I would guess..

I think that you may be thinking that the (lake) laser beam has to pass through a finite change in refracive index to bend, but I think it is the instantaneous gradient that causes the rate of change of direction..
 
I am not the best person to ask.. I imagine you will get some edge effects, but the main thing is that there will be a delay though one layer relative to the other. If that delay is a small fraction of a wavelength then when the two paths combine at some large distance there will be a _tiny_ offset in the position of maximum brigtness. For large delays and glass thickness (in term of wavelength) you would get a very fine-structured and messy interference pattern, I would guess..

I think that you may be thinking that the (lake) laser beam has to pass through a finite change in refracive index to bend, but I think it is the instantaneous gradient that causes the rate of change of direction..

Interesting. I was thinking of the laser beam essentially like a straight line of photon, but really you've got to to think of it a series of wavefronts.
20160826-140850-qzw92.jpg
So since the refractive index n varies between the top and the bottom of the beam, it kind of makes sense that there's the same sort of refraction, except it's continuous.
 
This is exactly the kind of sweeping statement I'm talking about. How can you say it's very flawed and in the same breath say that data hasn't been submitted yet? What are you basing that statement on exactly?

Um, I posted a long series of very specific points - why did you ignore them all to claim I'm making a sweeping statement and not supporting it?

And I asked you a number of specific questions which you have completely ignored.

Please review these 3 posts from page 11 in this thread.

https://www.metabunk.org/lake-balat...of-the-earth-if-any.t7780/page-11#post-189028
https://www.metabunk.org/lake-balat...of-the-earth-if-any.t7780/page-11#post-189032
https://www.metabunk.org/lake-balat...of-the-earth-if-any.t7780/page-11#post-189046

The critique is on the stated methodology IN EVIDENCE, not on the data. The data is irrelevant to method.

If what was STATED about the methodology is incorrect that's fine - show the corrected methodology and we will reevaluate it. I can only offer my input based on what we have been told. But this is critical...

DO YOU HAVE HITS ON THE BOARD AT 6KM OUT OR NOT? NOT CAMERA HITS-VIDEO RECORDED, HITS ON THE WHITE TARGET?

If not then you have a very serious issue. but I'm about done with this game you guys are playing. If all you have are 'camera hits' it's over.



For example, I don't care what measurements Hawking got because they didn't document the leveling procedure. Same situation here.

I don't care if Sandor shows the Earth is curved - I reject this "direct hit" in the camera measurement. Period. And I gave two EXTENSIVE analysis posts explaining why.


Is it possible to be disingenuous by asking questions?

EDIT: I left this blank by accident (got in a hurry).

My point was that refraction exists, both directions, and that Sandor will need to need to account for it - so you then challenged ME to 'prove' it was happening.

That is just not how this works and I think you know that.


My points again, which seem to be getting ignored are:
1. Laser levelling, is the laser level?
2. Refraction, we seem to observe only upwards refraction.
3. Beam divergence, we have observed wide beam divergence but it was an intermittent phenomenon, narrow beam divergence over long distances was also observed.

1. Not according to the ONE datum you've given us, appears to be pointing slightly up. I already post a DETAILED analysis of this that you are ignoring and claiming we ignored the question. We cannot answer this further UNTIL WE GET ALL THE DATA.

2. So? Are you saying normal downward refraction doesn't exist or couldn't have possibly happened? Fine, but Sandor will need evidence supporting this, is what I have said.

You can't just assume it.

3. You'll need to show that with the laser hitting the board at every distance for a valid measurement, in a still boat, with all persons remaining in the same positions for each measurement so the boat isn't tilting.

If we could assume for a moment that the laser was pointed upwards, the refraction was always upwards and the beam divergence was good, how would you explain the readings they got? (ignoring for the moment that the direct hit readings are not accepted as accurate).

You get upset when I comment on the things that HAVE been said - Why are you asking us about data we don't have?

But you do realize that upward refraction would make the data appear to show a curved Earth right?

Normal refraction is downwards - the inferior mirage you hit at 5am doesn't define the normal refraction case, that requires a separate demonstration. We can maybe/kind of tell what's going on by the visual effects at the water/land boundary but that's not perfect so is easily disputed.
 
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Um, I posted a long series of very specific points - why did you ignore them all to claim I'm making a sweeping statement and not supporting it?

And I asked you a number of specific questions which you have completely ignored.

Please review these 3 posts from page 11 in this thread.

https://www.metabunk.org/lake-balat...of-the-earth-if-any.t7780/page-11#post-189028
https://www.metabunk.org/lake-balat...of-the-earth-if-any.t7780/page-11#post-189032
https://www.metabunk.org/lake-balat...of-the-earth-if-any.t7780/page-11#post-189046

The critique is on the stated methodology IN EVIDENCE, not on the data. The data is irrelevant to method.

If what was STATED about the methodology is incorrect that's fine - show the corrected methodology and we will reevaluate it. I can only offer my input based on what we have been told. But this is critical...

DO YOU HAVE HITS ON THE BOARD AT 6KM OUT OR NOT? NOT CAMERA HITS-VIDEO RECORDED, HITS ON THE WHITE TARGET?

If not then you have a very serious issue. but I'm about done with this game you guys are playing. If all you have are 'camera hits' it's over.



For example, I don't care what measurements Hawking got because they didn't document the leveling procedure. Same situation here.

I don't care if Sandor shows the Earth is curved - I reject this "direct hit" in the camera measurement. Period. And I gave two EXTENSIVE analysis posts explaining why.








1. Not according to the ONE datum you've given us, appears to be pointing slightly up. I already post a DETAILED analysis of this that you are ignoring and claiming we ignored the question. We cannot answer this further UNTIL WE GET ALL THE DATA.

2. So? Are you saying normal downward refraction doesn't exist or couldn't have possibly happened? Fine, but Sandor will need evidence supporting this, is what I have said.

You can't just assume it.

3. You'll need to show that with the laser hitting the board at every distance for a valid measurement, in a still boat, with all persons remaining in the same positions for each measurement so the boat isn't tilting.



You get upset when I comment on the things that HAVE been said - Why are you asking us about data we don't have?

But you do realize that upward refraction would make the data appear to show a curved Earth right?

Normal refraction is downwards - the inferior mirage you hit at 5am doesn't define the normal refraction case, that requires a separate demonstration. We can maybe/kind of tell what's going on by the visual effects at the water/land boundary but that's not perfect so is easily disputed.
I think it's important just to clarify that Ian wasn't involved in any of the actual experiment on the day, he has merely been having private conversations with Sandor. I only say this because your use of "you've given us", and "you'll need to show" could be construed incorrectly by him, even though I believe you to be saying it that way as a general term. But you're quite right about everything you say.

Maybe @Ian Dalton could shed some light on my earlier questions as he has mentioned elsewhere that he knows what's going in the video. Has Sandor already reached his conclusion about the experiment? And if so will you tell us?
 
No worries, I believe most would have understood, but that alone could have sidetracked any potential response from Ian. And I don't mean to insult him in saying that either.
 
Without some way to quantize the diffraction of the laser and refraction due to atmosphere I think all may be lost on this run.

But let me throw some basic numbers out here...

Round Earth Slope

Let's say that over 700m we went from 125cm to 132cm - that's 7cm, 4cm of which would be curvature 'drop' so that leaves 3cm per 700m or just about 26cm over 6km for the rise due to angle above level.

So at 6km (before diffraction and refraction) we would expect the laser to be 283cm + 26cm = 309cm above the 125cm level.

(R1) slope = 3cm/700m
(R2) slope offset at 6km = 26cm
(R3) total rise at 6km = 309cm

I don't have any data to compare this with but that's the basic numbers.

Flat Earth Slope

Ok same thing on Flat Earth, it's 7cm/700m (no subtraction for curvature)

(F1) slope = 7cm/700m
(F2) slope offset at 6km = 60cm
(F3) total rise at 6pm = 60cm (same as (F2) since there should be no curvature)

In this case (again, before diffraction and refraction) the laser should be about 60cm above the 125cm mark.


Problem is... If the laser is up higher than +60cm then Sandor can legitimately wonder if refraction bent it up (diffraction only works in his favor in this arrangement I think), and if it's below +309cm we will legitimately have to wonder about diffraction spreading the beam and refraction bending it down (which IS the normal case).

Meanwhile, here is another question case -- why is there a big green laser stripe on his arm? In addition to diffraction of the beam, this could possibly cause false "camera direct hits". Suspect this is caused by internal reflections from the laser & collimator housing.



And if I may - "just LOOK at that laser, clearly pointing downward!"

so you can tell by this close up picture that the laser is pointing downward??? LOL
amm.... don't make a fool out of your self with claims like this...
it is leveled as just taking the pic after the 3rd experiment... and this is not a proof of leveling, but beam diameter at the start...

THE MATH YOU USED IS TOTALLY WRONG. Calculate DROP + LASER height

you better clear out your terms, they are FALSE HERE:

"diffraction spreading the beam and refraction bending it down "

diffraction is NOT spreading the beam.. it's divergence... but I have no idea what you wanted to say here..

refraction is not bending down...


"Meanwhile, here is another question case -- why is there a big green laser stripe on his arm? In addition to diffraction of the beam, this could possibly cause false "camera direct hits". Suspect this is caused by internal reflections from the laser & collimator housing."

Actually, if this was a PROSPERATIVE DISCUSSION FORUM, I would explain this very happy... like we have have 17 lenses to make the beam perfect, cut off all the other waveforms than the Gauss... and so on...


BUT IT'S NOT WORTH FOR ME TYPING HERE - SORRY!!!

I'LL DO IT IN A FORUM OR PRESENTATION WHERE PEOPLE DO RESPECT THE OTHER!
 
Well Mick, first of all I AM VERY DISAPPOINTED.
(I wrote this a PM to MICK but decided to place it as an answer 4 all 2 C)

Disappointed on your comments, and on your lack of understanding about the experiment details. AS WELL as your baseless claims - and NO EVALUATION of the presented material (other than you calculated some distances)

"This whole "leveling" and "slope correction" thing is basically irrelevant. You just need a series of accurate height measurements at regular intervals up to a sufficient distance. It's good if you can get the laser so it's not pointing down. When you have the measurements you can work out the slope of the laser and the curve of the earth.

However the measurements were not made.

Sandor knew how high the laser was supposed to go (6 feet above where it started in 3 miles, 10 feet in 4 miles), and yet he used a target that only allowed measurement of a few inches, if that. So the experiment yielded no results."

WHY? are you making statements, comments like this?

and the SAME FOR METABUNK COMMUNITY!

"Noraa Myles Landwehr It's not going to be conclusive evidence of anything... we've already determined from the data released that experiment has a plethora of fundamental errors even without all of the supposed data Sandor hasn't given... that you folks decided otherwise is immaterial. What's going to happen is that as soon as the video is released, people are going to point out these fundamental errors. Moreover, Sandor isn't going to try to get this peer reviewed as it will be rejected out right due to these errors.

It is seeming more and more the case that Sandor put this on metabunk to pretend it had legitimacy and never really intended to reach a conclusion other than the earth is flat regardless of the outcome. I don't really get why, because all he's managed to do is make it known that his experiment is fundamentally flawed and inconclusive (even more so than the Hawkings one) (even without the other supposed data) even before he got the video out... the thing is, we don't need to have any other data to confirm this... the data he has already released shows this extensively; and him releasing more data isn't going to make this suddenly not the case.

So this really brings the question: who is he trying to convince since everyone other than hard core flat earthers are going to reject this due to the aforementioned errors. Was the purpose just to exhibit confirmation bias and to create a fallacious video? It seems so"

Noraa Myles Landwehr What I just mentioned is also why Ian is seeing people telling him this very thing on metabunk whenever he posts... What are sandor and ian going to do: ignore what everyone on metabunk tell them and just declare victory? Seems to be the case. Again, why post the experiment on metabunk in the first place if you are just going to ignore what everyone tells you and declare victory? It certainly paints the whole thing with illegitimacy for sure..."


Bernard Mc Donnel:
"The facebook page however is a good judge of the type of person who follows the flat earth belief. This @Ian Daltonchap is a prime example. @Sandor Szekely told him something that relates to flat earth, and this experiment, and he jumps on it, someone like @Mick West refutes the claim and he's wholeheartedly skeptical."

SNaphat:
"We'll it seems less that they don't understand and more that they really just want this to be the end all experiment for the globe."

Darkstar
"They clearly don't understand what "slope correction" is."

Hama Neggs
"I believe that also applies to Sandor, as far as I can tell. I have posed a question to him regarding that, but no response so far."


Dark Star is the ONLY here who admits at least thet HE MIGHT NOT UNDERSTAND THE EXPERIEMNT WELL
"Thanks for the clarification Mick, I thought the 1.25m mark was the 717m measurement. I see now what they tried to do."

"ok I have been following this thread for a while and can I ask if the experiment collected any data? from my understanding we would get at the end of this a set of laser hight compared to distance. did they collect that or did they just go out and mess about on a boat? because to quote a mythbuster.

"the only diffrance between screwing around and science is writing it down""

MICK? ARE YOU SURE THIS IS THE TYPE OF SCIENTIFIC APPROACH AND DISCUSSION???

SO IS THIS WHAT I SHOULD BE DEBATING? COME ON PEOPLE! I HAVE NO ENERGY TO PLAY FOOL HERE! ESPECIALLY NOT LIKE I AM OFF FOR A DAY AND PEOPLE ATTACK ME FOR THAT!

YOU PEOPLE ARE A JOKE, NOTHING BETTER THAN TROLLS IN THE FACEBOOK PAGE...


NO THANKS!!! I WILL DEBATE THIS ON A REAL - REPEAT REAL - SCIENTIFIC FORUM.
WHAT A JOKE...

I THOUGHT YOU ARE SERIOUS PEOPLE... SORRY TO SEE THIS...
 
@Sandor Szekely, all we expected from this experiment is a graph of laser height vs. distance. You have not been able to produce this in the last 10 days. So there is nothing to talk about. You have not done an experiment.
 
@Sandor Szekely, all we expected from this experiment is a graph of laser height vs. distance. You have not been able to produce this in the last 10 days. So there is nothing to talk about. You have not done an experiment.


OHH YEAH? THEN WHY NOT WAIT FOR IT AND AVOID STUPID RIDICULOUS COMMENTS AND ATTACK ON ME??????

GOES FOR ALL OF YOU HERE !!

"You have not been able to produce this in the last 10 days. "

HOLLY FUCKING SHIT!! SO NOW I HAVE TO COMPLETE ALL THE DATA ON TIME?? ARE YOU PAYING ME FOR THIS?? lol

"So there is nothing to talk about. You have not done an experiment."

YES I AGREE, I HAVE NOTHING TO TALK TO ARROGANT PEOPLE LIKE YOU HERE...

( AMMM... ACTUALLY I DID DO 3RD AND 4TH EXPERIMENT DATA ANALIZYNG AND SHARED IT WITH MICK AND ALSO ASKED HIM NOT TO PUBLISH THEM UNTIL WE HAVE FULLY CHECK IT MAD MADE IT IN A NICE FORM)

YOU PEOPLE WILL HAVE TO LEARN : RESPECT

NAMASTE
 
It is also stated on this thread that a noted authority (Dr. Andrew Young) has stated that such a definative single measurement of this nature is not possible, by you (or Hawkins, by implication), due to (unknown) refraction (magnitude).
 
SO NOW I HAVE TO COMPLETE ALL THE DATA ON TIME?
In fact I expected the data to be available immediately after the experiment. After all, all you have to do is to write down the laser height at each stop in a notebook with a pencil. So by the end of the experiment you have all the data. Of course that assumes that you have a tall enough board to be able to measure the laser height. Which you didn't.
 
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