It might not be much, but the number would not be zero.
But it would be within the error of levelling it.
And seriously? kilokilometers?
Why not just use Mm?
Those tubes can be looked upon to take them out of horizon line. You know this.
Not unless there is significant distortion from the camera.
Otherwise, you cannot magically turn a straight line (such as a line connecting the water levels to the "horizon" for a FE), into not being straight.
So no, with that setup there is no need to have them perfectly aligned, and those photo show the horizon below eye level.
but imperceptibly so near sea level.
However, it still does not address the issue.
That, along with my previous post addressed the issue in 2 ways, first by pointing out that seeing the horizon or not is dependent upon the FOV, and showing the horizon is not at level.
The issue is.....there should absolutely, 100% certain, not be any horizon line....at all if we supposedly live on top of a globe.
WHY?
There should certainly be a horizon due to the edge of Earth. It is a Flat Earth that should never have a horizon, unless it is due to mountains or teh very edge as otherwise the limited visibility through the atmosphere would result in nothing more than a blur, similar to a very foggy day.
As for seeing it, unless you are up very high, or have a FOV of basically 0, you would expect to see it.
How about instead of just repeating the same refuted, false assertion, you actually try to justify it?
Such as by doing the math to show just how far below eye level the horizon should be, like I did for an eye at 2 m, where the horizon should be 2.7 arc minutes below level. So unless your FOV is tiny, less than 5.4 arc minutes, YOU WOULD EXPECT TO SEE THE HORIZON!
It doesn't matter how it's dressed up, the Earth should curve downwards from your level scope sight. Earth should disappear from your level sight almost right away...and this is only standing on a beach.
You mean it should drop to 2.7 arc minutes below level. i.e. a tiny amount.
If you are looking from a tower or a mountain or a plane and looking absolutely level, your Earth is gone, to be replaced by sky...only.
There would be no horizon lines.
By that insanity, if you were looking at a round object, like a basketball, you shouldn't be able to see any of it unless your eye was right up against it; balls, or any round object should be invisible.
A tower 1 km tall on Earth would be equivalent to roughly 1 hair width on a basketball. So by your lack of reasoning unless your eye was within a hair's width of a basketball, it should be invisible.
That is clearly pure nonsense.
Back in reality, the angle that Earth should subtend, at a given height h is determined by:
2*arcsin(r/(r+h))
Also note that this is the same formula as for any spherical object. You could even replace r+h with the distance to the centre.
Even at an altitude of 100 km, Earth should still take up 160 degrees of your FOV.
At an altitude of 1000 km, it takes up 120 degrees.
Again, you are literally saying that the only thing you would accept to show Earth is round, is something you wouldn't expect if Earth was round, i.e. something which would show Earth is not round.
i.e. you would not accept Earth is round based upon things which show it is.
There's plenty of stuff out there that verifies the Earth is not a globe we walk upon.
Like what?
Your strawman which in no way represents what you would actually expect a round Earth to look like or produce and thus in no way proves that Earth is not a globe?
Is everything that you have seen based upon either completely misunderstanding what you would expect for a RE or knowingly pretending you would expect something you shouldn't?