Possible experiment to determine curvature.

I thought of this experiment, but I am not sure how well it would work, or if anybody has the proper tools.

Somebody with a good camera and a tripod should find a high elevation right next to a large body of water, and setup the camera perfectly level. Then take several pictures and see where the horizon is on the camera. On a flat earth, the horizon should be exactly at the mid-point of the field of view, but on a round earth, the horizon should be a couple arc-minutes down. I am not sure if anybody has camera's that could detect that, but here is the formula for how many degrees down the horizon should be based on how high off the ground you are (the higher the better):

cos^-1(6371000/(6371000+h))=angle

h is measured in meters, and the angle is measured in degrees. At 1 meter up, the horizon should be 2 arc minutes down, but at 50 meters up, it should be about 13 arc minutes.

I am not a camera person, so I don't know if cameras that can see such a small angle exist, but if anybody does know, please say so.

I thought of this experiment, but I am not sure how well it would work, or if anybody has the proper tools.

Somebody with a good camera and a tripod should find a high elevation right next to a large body of water, and setup the camera perfectly level. Then take several pictures and see where the horizon is on the camera. On a flat earth, the horizon should be exactly at the mid-point of the field of view, but on a round earth, the horizon should be a couple arc-minutes down. I am not sure if anybody has camera's that could detect that, but here is the formula for how many degrees down the horizon should be based on how high off the ground you are (the higher the better):

cos^-1(6371000/(6371000+h))=angle

h is measured in meters, and the angle is measured in degrees. At 1 meter up, the horizon should be 2 arc minutes down, but at 50 meters up, it should be about 13 arc minutes.

I am not a camera person, so I don't know if cameras that can see such a small angle exist, but if anybody does know, please say so.

You can do what you want with a camera mounted on a surveyors theodolite or even a builders automatic level.      These instruments are extremely accurate.     You can hire a theodolite quite cheaply from many building hire shops.   The level of accuracy you are wanting is easily obtainable with these devices.

I figured there had to be something to measure that. Thanks. I can't actually do it myself since I'm a broke college kid, but if someone else wants to do it, it would be pretty undeniable proof that the earth curves (of course, the flatties would just ignore it)

I figured there had to be something to measure that. Thanks. I can't actually do it myself since I'm a broke college kid, but if someone else wants to do it, it would be pretty undeniable proof that the earth curves (of course, the flatties would just ignore it)

There is a surveyor already making youtube videos.  And yes flatties are not interested

That video doesn't work here by the owner's request. I watched it on youtube though.

My father was in consruction.
I was sometimes working with him when I was young.
He had to cooperate with geodesists sometimes.

Guy who made this video is not real geodesist.
And comments on his video are deliberately disabled.

EDIT:
This comment was my mistake.
I was addressing wrong video.
This guy IS real geodesist.

Somebody with a good camera and a tripod should find a high elevation right next to a large body of water, and setup the camera perfectly level. Then take several pictures and see where the horizon is on the camera. On a flat earth, the horizon should be exactly at the mid-point of the field of view, but on a round earth, the horizon should be a couple arc-minutes down.

Minor point: level camera at "high elevation" on a flat Earth...
the horizon would not ever rise up to mid frame.

Why not? You should be able to see really far away, and even if you see to Antarctica, you should see the wall. If it is flat, it should vanish at exactly the midpoint because that's how perspective works.

There are several apps for Android that work as theodolite.
Never tried any of them, but some people did.
Some are free.
I believe Dioptra is one of free ones.

Why not? You should be able to see really far away, and even if you see to Antarctica, you should see the wall. If it is flat, it should vanish at exactly the midpoint because that's how perspective works.

Parallel. Think it through.

My father was in consruction.
I was sometimes working with him when I was young.
He had to cooperate with geodesists sometimes.

Guy who made this video is not real geodesist.
And comments on his video are deliberately disabled.

Comments are disabled by his choice at the time, where he said he was new to the medium and did not want people saying unpleasant things when he was talking about his professional expertise and it was placed in a public environment.   His subsequent videos cover the subject in much more detail and comments are welcome.      Essentially the flatties are too cowardly to comment anyway.

How do human beings define 'real geodesist'.    Evidently unless he is lying he is working sometimes as a geodesic surveyor.   

But I am really confused by your comments.  What point are you wanting to make about this video?

Quote from: SpJunk on August 29, 2016, 07:15:04 PM

My father was in consruction.
I was sometimes working with him when I was young.
He had to cooperate with geodesists sometimes.

Guy who made this video is not real geodesist.
And comments on his video are deliberately disabled.

Comments are disabled by his choice at the time, where he said he was new to the medium and did not want people saying unpleasant things when he was talking about his professional expertise and it was placed in a public environment.   His subsequent videos cover the subject in much more detail and comments are welcome.      Essentially the flatties are too cowardly to comment anyway.

How do human beings define 'real geodesist'.    Evidently unless he is lying he is working sometimes as a geodesic surveyor.   

But I am really confused by your comments.  What point are you wanting to make about this video?

It was my mistake.

I saw lot of YouTube videos, and the beginning of this one reminded me of another one.
So, I didn't see the rest when commented as if it was that other video.

After your post I went to see the whole thing and realised where I was wrong.

My apologies.

There are several apps for Android that work as theodolite.
Never tried any of them, but some people did.
Some are free.
I believe Dioptra is one of free ones.

I downloaded the Dioptra theodolite app on my Nexus 6P phone before my Atlanta-to-Portland Oregon flight yesterday, and using it I took the photo below from 36,000 feet altitude.  Ignore the Lat/Long and Altitude data: the phone is in airplane mode and the last GPS fix it had was the Atlanta airport.  The pitch, roll, and compass sensors do not rely on GPS, so they work in airplane mode.  I leveled the phone as well as I could, within a degree of left-to-right roll and only 1/10 of a degree below level front-to-back.  I couldn't get it to hold steady at 0°, and of the various photos I took I opted to present here the "pointing slightly down" error photo to avoid being accused of "well, your phone is pointed above the horizon, so you must be trying to cheat."  As you can see, there is plenty of blue sky BELOW the dead-level position we are told to expect the horizon to be.  To the naked eye, the horizon LOOKS like it's at eye level, yes.  To an instrument, it measures at about 1 degree below eye level.  I don't have a photo with the theodolite's horizon matched up to the earth's horizon because the entire flight was over land (not likely to be level) and there were scattered clouds at every point that I took a look (obscuring the earth's horizon from view).