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:

View attachment 20170

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.