Keeping a small dot over one mile distance

[srow]

Thank you everyone! So which is best for my application, beam expander or 3 element lens??

Ha ha, I thought the mention of flat earth might provoke ridicule but I'm surprised at how much on a technical forum like this. I know of other experiments with telescopes and boats and horizons etc.. but none quite like what I'm doing. I know they all prove the same thing but I want to do something myself. I also know that if my experiment is successful there will be either silence from my critics or the will say it's due to refraction.

There will be someone at the other end but I will also be looking at the dot through a telescope at the firing end.

I searched for the previous thread on the similar experiment but am struggling finding it.

 

[RB astro]

Ha ha, I thought the mention of flat earth might provoke ridicule but I'm surprised at how much on a technical forum like this.

I searched for the previous thread on the similar experiment but am struggling finding it.

It's dropped off the face of the earth, so to speak. :thinking:

Haha, just kidding, please forgive me, I couldn't help myself.

:angel:

 

[Encap]

Thank you everyone! So which is best for my application, beam expander or 3 element lens??

Ha ha, I thought the mention of flat earth might provoke ridicule but I'm surprised at how much on a technical forum like this. I know of other experiments with telescopes and boats and horizons etc.. but none quite like what I'm doing. I know they all prove the same thing but I want to do something myself. I also know that if my experiment is successful there will be either silence from my critics or the will say it's due to refraction.

There will be someone at the other end but I will also be looking at the dot through a telescope at the firing end.

I searched for the previous thread on the similar experiment but am struggling finding it.

Here is the thread the about doing a similar thing: http://laserpointerforums.com/f44/10-mile-distance-laser-92273.html

It is not a simple a task in the real world as it is in imagination. see post #85 in the above thread which says:

"If your just doing this for fun, skip reading this post.
If you need a real measurement or this is a science fair project, read on...
Save your money and hire a surveyor.
Here is why:
So at 10 miles you will have atmospheric scintillation and refraction that does not quit.
Coherent light is subject to interference at the detector for each photon's beam path.
You get horrid low and high frequency noise. This is why light bulbs or Leds are used as sources for long distance light communications.

Next Question. How will you accurately find the centroid of the LARGE blob down range? Helps if your Blob is Guassian with a brighter center, but you would still have to find the center some how. This is going to need some serious robotics.
Or at least a photodiode/photomultipler sliding on a calibrated arm and a piece of graph paper.

The traditional way, used for surveying the Pacific Missile Range Islands by a team that included my Father...
Dad was helping with the planting of early Loran "A" NAVAIDs

1. Build a Bilby Tower at each end of the transit plus one offset a known distance on shore. This gets you above the small part of the refraction from ground convection.
2. Place a taped down Jeep Headlight on a leveled platform at the top of the first tower. The light is taped down to the central portion of the collimated beam.
3. Place a Theodolite or Transit on the other two towers. Measure carefully the spot of light, then swing the instrument to the other tower. Then swing upwards, catch a few stars at a precisely known time. Then Star site reductions at night to establish a Geodetic control point. These days differential GPS provided by WAAS or similar commercial services might get you closer. Then you still have to correct for the Ellipsoid.

Farmers and Road Builders hit milestones within inches with specially assisted GPS signals broadcast from temporary "control" stations and satellites. Often a local FM radio broadcast has the corrections on a Subcarrier.
You can lease/borrow the specialized receiver."

See also: https://en.wikipedia.org/wiki/Horizon

You could always just email this animation to people who imagine the earth is flat: http://eoimages.gsfc.nasa.gov/images/imagerecords/57000/57760/rotate_640.mpg

 

[olympus mons]

Ha ha, I thought the mention of flat earth might provoke ridicule but I'm surprised at how much on a technical forum like this. I know of other experiments with telescopes and boats and horizons etc.. but none quite like what I'm doing. I know they all prove the same thing but I want to do something myself. I also know that if my experiment is successful there will be either silence from my critics or the will say it's due to refraction.
.

Are trying to prove the earth is flat or spherical? You don't really think the earth is flat do you?

 

[srow]

Yes, I think the Earth is flat. There is too much evidence proving there is no curvature in the Earth never mind about all the other evidence.

I've read the '10 mile distance laser' thread and it was very helpful, thanks.

After reading the 10 mile thread I now know that you are all going to scream at me because I'm in the process of buying a "blue" 3W laser from sci-fi lasers with 3 element lens on his recommendation. If I'm not happy with it I can send it back as he(Eitan Atias) is guaranteeing it and then I could try a 520nm instead.

I don't think a distance of 10 miles is needed to prove no curvature when 1 mile will do.

 

[Teej]

Yes, I think the Earth is flat. There is too much evidence proving there is no curvature in the Earth never mind about all the other evidence.



I've read the '10 mile distance laser' thread and it was very helpful, thanks.

After reading the 10 mile thread I now know that you are all going to scream at me because I'm in the process of buying a "blue" 3W laser from sci-fi lasers with 3 element lens on his recommendation. If I'm not happy with it I can send it back as he(Eitan Atias) is guaranteeing it and then I could try a 520nm instead.

I don't think a distance of 10 miles is needed to prove no curvature when 1 mile will do.

Wait, what?

This isn't an academic exercise, you actually think the earth is flat?

:crackup::crackup::crackup::crackup::crackup::crackup::crackup:



Humans have KNOWN the earth was round for many many centuries.

The Phoenicians and Greeks for example knew it was round...they measured it, and, their guesses as to the earth's diameter were pretty close.

Basically, navigators, etc, knew it was round, because if they didn't, they could not do their job.

Using simple geometry, they calculated the distances to the moon, and various landmarks on earth, etc.

The myth that Columbus had a theory that the world was round and all is drivel...the ***tant, etc, a navigation tool he learned to use, assumed it was round before he was even born.

The only reason the navigators, etc, had to PRETEND, later, that it was flat, was that the Church would burn them for heresy if they said it wasn't.

The curvature was even taken into account for long bridges, etc.


So, if you are trying to PROVE its flat, you will either do the experiment incorrectly, or, find that it's round.



Was there a reason you were raised so as to not know this basic fact?

Or did you look at all the knowledge and data available, and figure this out all by yourself?

For example, you mention "evidence"....could you show this evidence?

 

[srow]

How can I do it wrong? I've just got to hold the laser(in a clamp) 15mm above the water and fire it across the one mile of lake. If the earth is round it will be impossible for the laser to appear less than 150mm(approx) on the other side. If the world is flat the laser will appear any where above 0mm or 15mm(approx due to water ripples). There is nothing to it.

So one of your reasons for the laser appearing below 150mm is that I will be doing it wrong! Any other reasons? Refraction or lying maybe?? I would love to hear all the reasons before hand so I can take them into account.

I was raised to believe the world was round like everyone else. There is tons of information on this subject. You really need to look it up.

 

[Teej]

How can I do it wrong? I've just got to hold the laser(in a clamp) 15mm above the water and fire it across the one mile of lake. If the earth is round it will be impossible for the laser to appear less than 150mm(approx) on the other side. If the world is flat the laser will appear any where above 0mm or 15mm. There is nothing to it.

So one of your reasons for the laser appearing below 150mm is that I will be doing it wrong! Any other reasons? Refraction or lying maybe??

You missed the point.

There were two potential outcomes:

1) You conclude the earth is flat.

2) You conclude the earth has curvature.


If you get conclusion #1, it means you did it wrong, because the earth is round, and this has been known by humans for most of recorded history.

If you get conclusion #2, it means you did it right.


A surveyor uses more accurate methods than you are employing, and concludes that the earth is round...essentially doing the same experiment, daily, for centuries of survey work...and, SEEING the curvature you feel is not there.

IE: Your experiment has been DONE already, everyday, for centuries, over and over again...by those equipped to do it even better than you are...over even longer distances.


So:

As for technique, as mentioned, sure, you can misalign it, not account for beam divergence, degree of leveling, etc.

It doesn't matter how you screw it up...if you conclude the earth is flat, you screwed it up.

Out of curiosity, please, could you list, out of the evidence you feel is conclusive and unquestionable, perhaps the top 10 reasons you used to conclude, that thus far at least, that the earth is flat?

We can then take that into account when advising on your technique, etc.

 

[srow]

You've just said the same thing. I'm saying IF any light from the laser appears at 15mm or less on the other side there will be no curvature on the lake(presuming I'm doing it right). Do you agree?

You say "As for technique, as mentioned, sure, you can misalign it, not account for beam divergence, degree of leveling, etc."

Beam divergence doesn't matter too much because if the earth is curved no light will appear below 150mm(approx) on the other side. It doesn't matter how much light appears above 150mm just as long as I see the cut off point/line/horizon. If light appears all the way down to 15mm or less then there can't be any curvature. As for leveling I just move the laser around until i see it on the other side and then try and lower it to 15mm. Isn't 'misalign it' the same as leveling? Do you agree?

I don't want to start a massive debate on all the evidence for flat earth. I don't think this is the forum for it. There are plenty of other sites for that.

OK, I will say that if anyone is interested in 'flat earth' there is an amazing book on the subject called 'zetetic astronomy' by Samuel Rowbotham. I don't agree with all of it but the bits I do agree on are a revelation.

The relevant math for the curvature of the earth is quite simple. The earth drops by 8 inches per mile squared eg. for a distance of 2 miles the curvature will drop by 8*2*2 = 32 inches. For one mile it is 8*1*1=8 inch. So, I'm firing a laser over about 0.95 mile at 15mm elevation and allowing 1/7th for refraction I'm saying no light will appear below 150mm(approximately).

 

[Teej]

You've just said the same thing. I'm saying IF any light from the laser appears at 15mm or less on the other side there will be no curvature on the lake(presuming I'm doing it right). Do you agree?

You say "As for technique, as mentioned, sure, you can misalign it, not account for beam divergence, degree of leveling, etc."

Beam divergence doesn't matter too much because if the earth is curved no light will appear below 150mm(approx) on the other side. It doesn't matter how much light appears above 150mm just as long as I see the cut off point/line/horizon. If light appears all the way down to 15mm or less then there can't be any curvature. As for leveling I just move the laser around until i see it on the other side and then try and lower it to 15mm. Isn't 'misalign it' the same as leveling? Do you agree?

I don't want to start a massive debate on all the evidence for flat earth. I don't think this is the forum for it. There are plenty of other sites for that.

OK, I will say that if anyone is interested in 'flat earth' there is an amazing book on the subject called 'zetetic astronomy' by Samuel Rowbotham. I don't agree with all of it but the bits I do agree on are a revelation.

The relevant math for the curvature of the earth is quite simple. The earth drops by 8 inches per mile squared eg. for a distance of 2 miles the curvature will drop by 8*2*2 = 32 inches. For one mile it is 8*1*1=8 inch. So, I'm firing a laser over about 0.95 mile at 15mm elevation and allowing 1/7th for refraction I'm saying not light will appear below 150mm approximately.

Your evidence is is books, such as the ludicrous zetetic astronomy, vs the combined knowledge of the entire world?

You didn't know he wrote that because he was defending the church's position on the subject? You didn't know the Pope, etc, recanted and admitted the earth was round?

IE: No need to pretend its flat for religious reasons anymore.



OK, wrong forum.


You know we can see the earth is round from space though, right?

:na:


The bottom line is the same.

If you do it right, you'll see its curved...just like the people who have done this same experiment, properly, for hundreds of years have also found.

If you do it 15 mm above the surface, BECAUSE of the earth's curvature, yes, refraction WOULD bend the light and cause optical errors.

Surveyors, etc, account for that to make accurate surveys.

IE: To be done more correctly, and not come to a false conclusion, you'd need to be higher up, and pick a target on a buoy or pole, etc, the same length as your laser/telescope, etc.

You'd also need to account for temperature inversion effects, etc, which can also interphere with optical methods. (Mirage-like effects, etc)

So to be even ball park conclusive, a 15% correction (~ your 1/7) would be applied, w/o even actually measuring the temperatures of the air at various points from your laser to your target....and that's fine, but, w/o the measurements, the difference could be more than that, etc.

 

[srow]

You already know my opinion of space and NASA.:tinfoil::tinfoil:

I know what results I will get from my experiment so I'm going to take photos of my aparatus and you can tell me where I've gone wrong.

 

[Koff]

 

[Eudaimonium]

@srow,

Are you an open minded individual? In other words, should an experiment produce a result you were not hoping for, are you prepared to change your mind and beliefs about it?

Think about it really hard.

If you are not prepared to change your opinion given the objective proof - then why do the experiment?

If you ARE prepared to change your opinion in the face of facts (and many people for some reason aren't, it's like as if anybody would judge you to say 'I was wrong and I now believe differently') - then by all means, do go ahead. Just ask yourself if dipping hundreds of dollars into an experiment is the only way to obtain this information.

If you're looking for alternative methods, say, have you ever used a GPS device? What's your interpretation of how they work?

There's a small ton of apps for modern phones which provide GPS assisted VR image, for example superimposing your desired destination over your camera's image on the screen. I think Google Earth / Maps should have similar functionality - simply set your location to something on the other side of the country and use your camera to find it - you'll probably find faraway locations to be noticeably below horizon line.

EDIT - Also I'm curious as to what exactly is the "evidence [that the Earth is flat]" that you speak of. Care to elaborate? You mention one needs to "look it up" but you shouldn't use that expression when trying to change anybody's mind - the only thing I'm gonna find when "looking it up" is information that supports my belief. That's why I believe it in the first place.

 

[Pi R Squared]

If the earth were flat, we should all know where the edge is, plenty of people would have found it. What is on the other side? We should be able to get there to take a look. I wonder if we could drill a hole through to the other side. If you fly in a jetliner on a clear day when at high altitude looking at the horizon you can see some curvature, is this an optical illusion?

Alan

 

[Teej]

If the earth were flat, we should all know where the edge is, plenty of people would have found it. What is on the other side? We should be able to get there to take a look. I wonder if we could drill a hole through to the other side. If you fly in a jetliner on a clear day when at high altitude looking at the horizon you can see some curvature, is this an optical illusion?

Alan

He quotes a book written in the1800's, everything in it was debunked THEN...

The people who did the experiments, bet against those who said they were wrong, lost the bet, and then sued because the other people knew they were wrong and took advantage of them.

IE: Betting with someone as to the outcome of yesterday's game...when you saw the game, etc.

The first source he quotes was proven wrong back when the book was written......and that's his attempt to show evidence....a long ago debunked mistake by a man who didn't know anything....and, didn't know what he didn't know.


Sailing west as a shortcut to the east WORKS....because the earth is round.

If it didn't work, ships would, as Alan pointed out, fall off the edge instead of getting to where they wanted to go.

 

[srow]

Thanks Koff!

Eudaimonium, You sound like you really don't want me to do this experiment. I will post the results which ever way it goes. It doesn't really affect my life in any way. I'm easy with what ever comes of it. Do I sound like I'm biassed? What does it matter to anyone what the results are? If I prove the lake to be flat I will be ridiculed and dismissed as a lunatic so you shouldn't be afraid of whatever I find.

PIR squared: That's right, drill to the other side like a brick wall.

Anyway, talking to you critics has given me another idea. If I find the lake to be flat I will float a 50mm thick piece of wood or whatever in the middle of the lake to mimic the supposed curvature of the earth to see what the results would have been.