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Messages - Longtitube

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21
Righto, here's where I'm getting 10px from:



You pointed out inaccuracies in my version and Regicide's attempts to measure the horizon sagitta, so I expect you to apply the same standards to your own . Your purple straight line is not aligned with the left of the horizon. I measured from where the white area becomes pale blue at either side: yours goes from the middle of the pale blue at left to close to the transition at right. The "increased contrast" version I have been unable to reproduce by merely increasing contrast in my own bitmap editor, but if you can give me a link to the Bad Acid plug-in used I'd be obliged: I have an unrelated use for it in mind. For the purposes of this discussion it's useless and your result of 11 pixels invalid. Indeed, you're on shaky "Photoshopped" grounds there, see the wiki FAQ.


Oh, while we're at it, let's verify your "3px" estimate for the tray. I'm not sure why I chose not to question it before, but...



In a truly shocking turn of events, it's actually 7px.

Well, let's have a closer look again. My measurement was across a width of 715 pixels and I was very interested to see yours being across 776 pixels. Big deal, you may say, but I was very careful to avoid the curved area at either end of that seam, something you haven't done. At the left side especially, your measurement clearly strays into that curved area to the benefit of an increase in sagittal measurement. Tut, tut. I'm not saying you are being disingenuous, but both these measurements are sloppily done, so both are invalid.

Finally, you mention Tiny Round Earth, a term I'm unfamiliar with. I don't know whose tiny round head is supposed to have mentioned the subject, but it wasn't me, and I couldn't find it on the forums or the wiki. Could we have an explanation? With calculations for the result you claim?

22
fish eye lenses start at 100° FOV. Secondly, the lens you propose this is is only a tiny bit away from a fish eye in terms of focal lengths.

You really try to force ratios where they don't belong. It does not inspire confidence.

Really? Name an APS-C fisheye lens with a 100° field of view: not a rectilinear wideangle, a curvilinear lens. Then demonstrate how the video we're all discussing is shot using a fisheye lens.

23
It'll be a bit more complicated than that - to get any number for direct comparisons, we'll first need to establish which barrel distortion formula to use. This is one of the reasons why I'm advocating for a visual solution, rather than a numerical one.

Which barrel distortion formula? Can't you handle the algebra for arcs? It's given on the page for that sagittal calculator; any O-level schoolboy should be able to do the calculations.

I should be clear: I already have a good enough idea of the equipment used. That's what enables me to speak with a decent amount of confidence here...

Then please don't describe a lens as "bordering on fisheye" when it is anything but. A fisheye lens has a field of view of 180 degrees, more than twice that of an 18mm on APS-C.

I look forward to your own arbitrary arc drawing, since you had little difficulty with Regicide's screen captures:–

EDIT: For the absolute avoidance of doubt, here's your screenshot with the actual horizon traced correctly:

24
The ratio between the "line" and "dip" have nothing to do with the eccentricity of these two arcs. I can keep pointing out that you're wrong and explaining why you're wrong, but in the end of the day you won't accept it, because you're not interested in being correct - you just want to confirm your preconceptions.

But hey, let's keep on keeping on. Let's illustrate the issue with my previous example:

The span of the white frame is 590 pixels, and the "dip" (sagitta) of the first arc is 14 pixels.

The second arc has a span of 195 pixels and a sagitta of 1.5 pixels.

You assert that I can make these comparable through a simple ratio. Let's do that.

1.5*590/195 = 4.53

As you can see, by your logic, I should expect that the arc towards the bottom of the image is much less curved than the one closer to the middle. However, even a cursory visual comparison will reveal that not to be the case. In reality, when measured correctly, the sagitta of the second arc is 23 pixels.

Very good, Pete, I always enjoy the chance to learn something new, and found a handy sagittal calculator should anyone like to check the following figures. https://www.liutaiomottola.com/formulae/sag.htm

The arc of 715 pixels has a measured sagitta (couldn't remember the term - thank you) of 3 pixels – this corresponds to an arc radius of 21302 pixels. The same arc extended to a width of 1117 pixels would generate a sagitta of 7.3 pixels, so yes, a simple proportional calculation is wrong. So near the bottom edge of the screenshot we have an equivalent full-width distortion of 7.3 pixels and barrel distortion of a straight horizon line much nearer the middle of the image would show distortion of rather less than that.

You also entirely ignored the many issues with your "23 pixels" estimate - the line you're using as your reference point does not touch the horizon on either edge of the frame (or, indeed, at all). When adjusted appropriately, the correct sagitta is more akin to 10 pixels.

Fair point about the red line in the screenshot, so I had my own try at it. I do hope the (black) line is distinct enough this time:–



Oh dear, "akin to 10 pixels"? Did you try measuring it yourself? My point still stands – if the tray seam (assumed by both of us to be straight) has distortion equivalent to 7.3 pixels across the entire frame, an assumed straight horizon close to the middle should show much less distortion, not more than twice as much. I attach very slight importance to your claim – if these words mean anything.

The lens was an 18-135mm zoom
Do you realise how extremely wide this range is, and how useless that statement is as a result? An 18mm focal would be bordering on a fisheye lens, which this obviously isn't. A 135mm focal wouldn't capture anything remotely close to this wide an area. Before you can perform your experiment, you need to know the actual focal of the lens at the time of filming, not what the particular device is capable of.

Dear me, I should have made abundantly clear the 18-135mm zoom lens is the one that took the test image of the grid, not the view from tens of kilometers above Earth. I do apologise for the misunderstanding, the intention was to demonstrate barrel distortion in a known, measured case and yes, I do understand how wide this range is.

But do you know the film or sensor size of the camera that this zoom lens was attached to? Was it perhaps a phone? Or a 35mm camera? Perhaps a micro 4/3 DSLR, an APS-C digital camera, a medium format or even an 8"x10" field camera? I'll spare you, it was fixed to an APS-C digital camera and 18mm is a typical wideangle focal length on an APS-C camera, with a 76 degree angle of view across the diagonal. Nowhere near fisheye with this camera format and I do hope this helps you.

..claiming that the Earth is round but 5 times smaller than in RET...

Eh? You must be confusing me with someone else.

Oi now, governor. There is absolutely no need to get personal, innit.

Praise be, the man has a sense of humour! Until next time, mate.

25
Flat Earth Projects / Re: Experiment with Braided Line
« on: September 24, 2020, 09:19:01 PM »
Yes, 10,000m is going to sag. A lot!  :'(

26
I'm sorry, but I'm not really interested in your whataboutism
....
It's strange that you're so desperate on this particular point, too.

There's no need to get personal, mate, even if you were right about desperation (which you aren't.)

you're also comparing the curvature of two arcs of different spans by simply measuring the difference in their chords

You're quite right, so I measured the length of the straight blue line by the tray's seam, originally highlighted by yourself. It's 715 pixels.




The tray seam, shown as an arc in the screen capture, dips 3 pixels below the long straight blue line. Were it the same width as the image, 1117 pixels, it would dip (1117/715) x 3 = 4.6 pixels. This is still sustantially less than the estimated 23 pixels the horizon rises above the straight red line, in fact about a fifth of the rise.

I repeat the general point about barrel distortion being important near the edges of an image, whereas it's very slight near the middle of the same image. I've seen many images displaying barrel distortion over many years and many showing much more distortion than the screenshot. Distortion affecting the middle of an image more than the edges is not barrel distortion, and is not evident in the screenshot.

I deliberately do not intend to process the image for distortion in Lightroom or any other program, because we have both seen many claims over the years that this, that or another image can't be trusted as it's been "Photoshopped" and we both know the pointlessness of such arguments. Indeed, the wiki makes this very point in the FAQ.

Yours must be a thankless task, moderating forums populated mostly by people who doubt or outright reject the flat earth hypothesis. Another week and another sceptic with experience and real-world knowledge asks difficult questions casting doubt on another part, or from another angle on the same part as last month, which the believers here struggle with. I'm sure you must groan at the next hazy, wobbly video shot over miles of water to make or disprove the case for the horizon or ships disappearing over it. It's not for the money anyway!

However, should anyone throw the barrel distortion problem back into the mix, you have an example to produce in answer – I'll leave the original test chart where it is. The lens was an 18-135mm zoom, the chart image was lifted directly from a review of that lens. What does surprise is the FAQ suggests a curved horizon will be seen from high up: I'd have thought you'd welcome the video evidence of such.

27
Thank you so much.

You earlier said the visible seam on the garlic bread tray demonstrated barrel distortion was present. It is, although very mild, so here's what a uniform, straight-lined grid looks like viewed through a lens with strong barrel distortion, with green lines in the middle of the picture:–



These green lines are straight, showing there is no horizontal distortion along the vertical green line or vertical distortion along the horizontal green line, but the further away from the middle you look, the stronger the distortion becomes. At the edges the distortion is unmistakeable.

Now here is the screen capture first posted by TomInAustin, with the amount of distortion showing on the tray seam marked in blue and the amount of curve in the horizon marked in green.



Near the edge of the image, the distortion measures 3 vertical pixels and we would correctly expect 3 or 4 pixels in the opposite direction near the top of the picture, while also expecting less distortion nearer the middle of the capture.

That is not what the capture shows: the curved horizon is only a short way above the middle of the picture, yet is curved by at least 23 pixels. That's not what mere barrel distortion would show. The horizon is plainly curved.

28
I beg your pardon, the screen capture was in TomInAustin’s post:-



Which part of the image was the “middle” again?

29
Flat Earth Theory / Re: Lake Minnewanka
« on: September 22, 2020, 08:32:23 PM »
https://thebanffblog.com/lake-minnewanka/

Quote
You have a wide range of options for boating on Lake Minnewanka that include canoes, motorboats, kayaks or even stand up paddleboards. If you’re seeking more of a challenge or to experience canoeing on open water head to Lake Minnewanka. The large lake is well known for its “swells” that occur when the wind gust picks up. More advanced paddlers with their own canoes can plan multi-day camping trips along the lake.

So we have lake known for swells, at a time when the waters are a bit choppy (windy).

As is Monterey Bay, just ask surfers and windsurfers, but being known for swells does not mean swells are always present. We could argue the Bishop Experiment is impossible because the Bay is known for fogs, but you know fog is not always present.

Perhaps you'd demonstrate these swells from the video? Please include those larger than 10cm.

30
Pete claims "very obvious" barrel distortion, but I wonder if he has thought this one through. There is very mild distortion (tray seam line dips down a little in middle) consistent with barrel distortion at the bottom edge of the camera view, the sort that most photographers would tolerate. This distortion would be reversed at the top of the camera view (straight line would rise up a little in middle) and be of a similar amount.

However, nobody has demonstrated distortion across the middle of the camera view, where the horizon is shown in the screen capture displayed in the OP. Barrel distortion would not distort the view there, perhaps Pete is thinking of a bottle bottom lens?  http://cameramaker.se/Coke_Lens.htm

31
Flat Earth Theory / Re: Lake Minnewanka
« on: September 22, 2020, 11:57:37 AM »
Right. Except in the Bishop experiment it says:

Quote
On a very clear and chilly day it is possible to see Lighthouse Beach from Lovers Point and vice versa. With a good telescope, laying down on the stomach at the edge of the shore near Lovers Point 20 inches above the sea level it is possible to see people at the waters edge on the adjacent beach 23 miles away near the lighthouse. The entire beach is visible down to the water splashing upon the shore. Upon looking into the telescope I can see children running in and out of the water, splashing and playing. I can see people sun bathing at the shore and teenagers merrily throwing Frisbees to one another. I can see runners jogging along the water's edge with their dogs. From my vantage point the entire beach is visible.

https://wiki.tfes.org/Experimental_Evidence#The_Bishop_Experiment

Hum. I always wondered about that account, the children splashing and playing in the water and people sunbathing on these clear and chilly days. Hardy lot, these Californians, much hardier than I remember.

Anyway, the main problem with the Bishop Experiment is the only evidence is Tom Bishop’s account. No photos, no video, no witnesses and he hasn’t got the telescope any more. Not what you’d call a watertight case.

32
Flat Earth Theory / Re: Gravity - measurement and applications
« on: September 19, 2020, 09:37:27 PM »
Are we missing the elephant in the room here? 

This thread has moved on ("gravitated", if you will) to discussion of hypotheses for the documented stable variations in gravity in different parts of the Earth under a RE model.  There is no sign of agreement, but there is at least one hypethesis. 

What is the FE/UA hypothesis, if the whole Earth is accelerating at the same rate?  Are some parts being left behind?

What has happened here is what has happened so often in the past: someone asks a difficult question which the FAQ and wiki don't answer and someone, by muddying the water, avoids answering the question. Several pages of irrelevant discussion ensue and the original question is forgotten.

Variations in the strength of gravity are documented from many locations, so how does FE thinking account for these? Several answers are possible, including "We don't know" - or - "No idea, but this person (link supplied) should be able to answer your question" - or - "There are no variations, there's no such thing as gravity. Read up about Universal Acceleration, duh."

Instead, we have in order:–

(1) references to not measuring in a vacuum chamber. which is meaningless without context, and vague references to underground density variations affecting gravity (which the OP asked for an FE explanation of)

(2) attempt to dismiss gravity variations as seismic noise in the gravimetric signal, ignoring the great difference in the period of low-frequency gravity variations compared to much higher frequency seismic noise and quite ignoring the vast difference in gravity signal size compared to the noise level in the signal (signal to noise ratio exceeding 1000:1). Additional attempt to make out the gravimeter is only a seismometer by producing graphs from a scientific paper which the poster does not understand, confusing signal noise at  the nano scale with the main signal variations at a minimum of micro scale, again at least 1000:1 difference, often much more.

(3) challenged on grounds of evidence introduced by the FE responder, attempt to dismiss this evidence as crude experimentation, alleging weights are piled indiscriminately directly on to expensive, sensitive gravimetric equipment and affecting instrument's sensitivity. Simple arithmetic refuting this claim, using figures from that evidence and manufacturer's data, ignored.

(4) FE responder introduces another scientific paper on gravimetry to dismiss mathematical methods used in processing results in the paper as mere guesswork and deception. Note to responder: the complete lack of mathematical understanding demonstrated here is not just laughable, it's embarassing. Please, for your own sake, don't do that; you're only inviting ridicule.

(5) repeated misunderstanding of effect of changes in nearby masses or height on gravimeters.

(6) introducing Bouguer anomalies into response without any understanding of what these are, despite earlier quoting an article from the Aligarh Muslim University which explains them

(7) dismissing gravimeter as a crude tool whose results can be interpreted any way, ignoring the necessary field work which follows a gravimetric survey.

(8/) attempt to make theories of mountain building part of dismissal of gravimetry, using case of fold mountains – an archaic term not used in geology since the 19th century

(9) irrelevant squabble about symmetry in geological and iceberg formations, concluding with challenge to show how mountains form

That is how the original question is avoided, as the regulars here know all too well. By now we're at the end of three pages of increasingly muddy waters, none of which gives an FE explanation for the well-documented variations in gravity in many parts of the world.

Just what explanation does FE theory have for this variation? If there's currently none, just say so.

33
Flat Earth Theory / Re: Gravity - measurement and applications
« on: September 16, 2020, 06:22:41 AM »
If you watch the reading of a barometer from a closed, windowless room you are unable to say confidently what the weather will be. Does that make the barometer an unscientific piece of junk? Hardly.

If you smell fungus growing in a spare room, does the damp meter used by the man investigating this tell you there’s a tile missing from the roof, or a big crack in the wall or does it pinpoint the leaking water pipe in your attic? It does none of these, but it does tell you the wall is damp in the area at the top of the far wall instead of the near left bottom corner. Obviously this makes it useless pseudoscience by your reckoning.

These are the grounds given for discounting gravimetric measurements, because Tom doesn’t believe in gravity. Not because it doesn’t work - geologists have used gravimeters for years as a valuable tool in their armoury - but because Tom doesn’t believe in gravity.

So tell us all - what valuable observation or prediction has UA ever made? There are none. 

34
Flat Earth Theory / Re: Gravity - measurement and applications
« on: September 15, 2020, 09:37:31 PM »
The wiki entries Tom quotes should be read to avoid misunderstanding, in particular following the links within these entries. If you do this, you find the quotation

Quote
    "This map shows the Bouguer anomalies over the whole of Germany and surrounding areas, in a detailed but still clear way.

    ...The resulting gravity anomalies vary across the mapped area from -170 mGal in the Alps to +40 mGal around the gravity low in the Magdeburg area."

but if you read the source, it goes on as follows:–

Quote
The resulting gravity anomalies vary across the mapped area from -170 mGal in the Alps to +40 mGal around the gravity low in the Magdeburg area. In the mapped area they form local structures such as the salt diapirs of north Germany, as well as regional units such as the Rhine Graben. Previous inconsistencies along the former German-German border have been removed. Anomalies can be used to interpret the geological structure of the Earth's crust.

In short, the gravity anomalies can be used to work out what's going on beneath ground level, which is what Iceman2020 originally stated. Perhaps Tom sees the word "anomalies" as meaning something is wrong, which is rather short-sighted.

The wiki also quotes "one writer" on gravity – why not name this "one writer"? Could it be because the writer is one David Pratt who unquestioningly documents many cranks and frauds who have made "discoveries" which no-one can replicate and are openly mocked by engineers and scientists who actually work in the relevant fields? Perhaps this "one writer" is less than reliable in his own comments about gravity too.

The word "dampened" gives Tom great trouble, he must be thinking of "dampening down" a fire, a much-desired thing in the US West coast states at the moment. What is meant by "dampened" in instrumentation is removing noise or extraneous vibration. A modern speedometer has a dampened readout and reads a steady 88mph when you're doing 88mph, whereas an undampened needle might continually oscillate between 84 and 92mph. Dampening the readout does not reduce the readout, just steadies it.

If you examine the results of raising an iGrav gravimeter on a lifting platform and later lowering it to its original position, you'll see significant noise in the readout after raising the platform which soon dies away. Nearly 24 hours later the iGrav is returned to the lower position and more significant noise is encountered at first which soon dies away. In each case, for the most of a day afterwards the instrument recorded a pretty steady reading. This is an example of a dampened noise signal – the noise quickly dies away. The experimental results (of a lesser pull when the instrument is raised) stand.



35
Flat Earth Theory / Re: Gravity - measurement and applications
« on: September 12, 2020, 07:27:36 PM »
Ah, I understand now! The manufacturer states the height of the iGrav is 102cm when fully assembled, but you have spotted a stray red plate that invalidates their measurements, completely. Obviously I should have seen that in the beginning – just can't trust manufacturer's data. Thank you so much.

edit: You can get a good idea of the physical size of the iGrav from the video. 102cm is around waist height, as may be seen in the video and 120cm is about armpit height on a six foot adult. 132cm is more like shoulder height on the same adult, noticeably taller than an assembled iGrav. That red plate is fixed to the Dewar – the flask of liquid helium. The coldhead gets bolted to the top of the Dewar via fixings in that red plate, which you will see if you watch the video through.

36
Flat Earth Theory / Re: Gravity - measurement and applications
« on: September 12, 2020, 07:01:39 PM »
I know some people struggle with arithmetic, but I didn't think it was something that troubled you. The weighted boxes were 132cm above ground, the iGrav is 102cm tall. That makes a 30cm gap between the top of the assembled iGrav - the complete, all pipes and wires connected, iGrav – and the weighted boxes supported by cabinets placed either side of the iGrav and not shown in any photos from that research paper. 30cm is almost 12 inches. Big enough to get both hands through, easily.

Or perhaps you're doubting photographic evidence. Again.

37
Flat Earth Theory / Re: Gravity - measurement and applications
« on: September 12, 2020, 06:40:59 PM »
Look up the word "conflate", Tom. You are applying the explanation of Experiment A to Experiment B, when they are not the same. Also, if you care to look up the iGrav manufacturer's information, you will see the sizes given include what you have circled, the "cold head" of the device. It's still only 102cm tall fully set up.

The connections to the platform you point out are not in fact bolted or screwed to it, they only rest on it. There's a handy video on the iGrav site on moving it which will show what all the pieces are.


38
Flat Earth Theory / Re: Gravity - measurement and applications
« on: September 12, 2020, 06:14:30 PM »
Show me.

It says:

Quote
4. Designed laboratory experiments

4.1. Monitoring mass change

In order to test the sensitivity of the iGrav, three boxes with
known weights were placed on top of the iGrav. Before doing
this experiment, we provided extra support (two cabinets) to
the platform
and let this situation become stabilized. The three
boxes with a total weight of 92.8 kg were then positioned
on the top of the platform, the height of which was 132 cm
from the ground.

It says they placed the weights on top of the gravimeter.

The cabinets were placed as extra support to the platform.

Then they took the weights off the gravimeter and put it onto the platform. The gravimeter readings returned to their original state.

From elsewhere in the document:

Quote
We put the iGrav on the platform of the lift table and measured the residual gravity without periodical effects (figure 9).

The 'platform' is something the gravimeter is resting on.

Yes, the platform is something the gravimeter rests on, but beware of conflating two calibration experiments. The experiment you're questioning has the gravimeter on the ground – typically a concrete block – and cabinets either side of it. Here is the iGrav device loaded in the back of a Honda SUV:–



and this is the device set up for use:–



Now, the weights mentioned were placed "on top of" the iGrav at a height of 132cm above the ground. The iGrav is 102cm tall when set up, and its core sensor (in the middle of the device) is explicitly mentioned as being 52cm above the ground. So there was a gap between the top of the iGrav and the weights in the calibration experiment of up to 30cm (approx 1 foot). There is also nowhere to set heavy boxed weights directly on the device, so your objection is bogus.

All relevant sizes of the iGrav can be found on their website:– http://www.gwrinstruments.com/igrav-gravity-sensors.html#Ease-of-Operation-And-Portability

The other experiment I mentioned involved placing the iGrav on a liftable platform and when raised the device measured a reduction in gravitational deflection:–




UA cannot account for a reduction in gravity in such circumstances. Gravity has been investigated and demonstrated for some centuries, UA has not.

39
Flat Earth Theory / Re: Gravity - measurement and applications
« on: September 11, 2020, 09:58:20 PM »
This is a poor setup. The gravimeter is very sensitive to noise. Placing a mass on top of the gravimeter can change the dampening. .... This experiment should  be done with the mass suspended over the device without touching it.

Reading a little more carefully, you'll see two cabinets were placed either side of it to make a platform to support the weight above the SG and left for some hours to stabilise. The reduction in gravitational reading is, like the reduction by raising the SG on a lifting platform, difficult to square with Universal Acceleration. Indeed, if the methodology is so poor, why is it cited by a number of other scientific papers on applications of gravimeters? Scroll down your original link and you'll find them.

40
Flat Earth Theory / Re: Gravity - measurement and applications
« on: September 11, 2020, 06:44:25 PM »
It would help if we had some survey data of some sort to see what Iceman2020 is describing, whether a gravimeter can detect different densities of below-ground deposits. Happily, Tom has supplied a link to some: if you follow his link to the "SG Raw Gravity graph" etc, you can scroll down a little to a download of the full scientific paper – https://www.researchgate.net/publication/264122117_Detecting_small_gravity_change_in_field_measurement_Simulations_and_experiments_of_the_superconducting_gravimeter_-_IGrav/download

It's a very interesting read, investigating whether a superconducting gravimeter could be used to monitor in-ground storage of carbon dioxide for reducing global warming. The calibrating experiments include one where a heavy weight is placed directly above the gravimeter to see if any change in the downward, Planet Earth-induced force of gravity is found, plus another to measure any variation in gravity when the instrument is simply raised a short distance above the ground, but I won't spoil your enjoyment by posting spoilers. Suffice to say, the idea of Universal Acceleration struggles to explain the results found.

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