You might hear some FE logic, or be shown a horizon seemingly following a camera being moved up and down, but never will flat earthers attempt at measuring if the horizon is eye level at high altitude.
Plenty of REers have done this, using all kinds of methods, but FEers always claim faulty measuring or logic, because they cannot believe the results.
You are basically blind to the truth.
An REer was the one here who said that the horizon rises to eye level. He was corrected, and I also was corrected, a correction that I accepted because after research it was shown to be better supported than the initial claim. The REer has yet to accept the correction. How does this make me blind to the truth?
I find the the often used claim, "Horizon rises to eye level", very ambiguous and virtually meaningless as it stands.
For a start, just what is "eye-level"? It is usually just assumed, though not explicitly stated to be the local horizontal.
Then, of course, whether the earth is a Globe or flat
the horizon does not rise at all, so the horizon never actually rises to "eye-level". Though it certainly seems to rise, due simply to perspective making to small distance down the horizon seem very small.
On the flat earth, since the horizon would be some indefinitely large distance away, the horizon would always
appear to rise to the horizontal - eye-level.On the Globe the situation is more complicated. The distance to the horizon now varies with the height of the observer.
This distance can be calculated with one of the usual equations.
Now it will be found that the horizon is always twice the observer height below the observer.
This horizon is, however, so far away compared to this dip that the horizon still does seem to "rise" almost at the local horizontal - eye-level.
But the horizon the Globe, neglecting refraction, is always a small visual angle below this local horizontal.
Neglecting any refraction we get these horizon distances and dip angle to the horizon
From 1.5 m above sea-level, the horizon is about 4.4 km away and 3 m below eye level. This makes the horizon only 0.04° below eye-level - quite imperceptible!
From 100 m above sea-level, the horizon is about 36 km away and 200 m below eye level. This makes the horizon 0.32° below eye-level - measurable with good instruments!
From 1000 m above sea-level, the horizon is about 113 km away and 2000 m below eye level. This makes the horizon 1.0° below eye-level - easily measurable.
And from 10,000 m above sea-level, the horizon is about 357 km away and 20,000 m below eye level. The horizon is now 3.2° below eye-level - barely detectable to the unaided eye, but easily measurable!
So, while the horizon does in fact not rise but falls, it does appear to nearly rise to that level, certainly up to 1,000 m or so. This because the 2,000 m drop to the (Globe) horizon is over a distance of 113 km - or only 1 part in 56, so quite close to level.