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tl;dr You need a camera and either a long lens or a telescope that'll hook to it to see how parallax lets you view the moon from different angles.

So, the moon always shows one face to Earth. Round Earthers believe it's because, despite the moon being a sphere, it's "tidally locked" to Earth and stuck in that position. Sounds suspicious, eh?

Well, Round Earthers also believe we are also on a big sphere, and that sphere is constantly turning. If that's true, we're also shifting in position in relation to the moon. If the moon was a sphere you'd be looking at it from different angles, wouldn't you?

Well, turns out you can. If you can take good quality photos of the moon at dawn and dusk you'll see the moon from different angles. If you take a number of different photos over night and string them together you'll be able to see the angular change. With a good view (you'll need a 1000mm equivalent lens or better) the 3D motion is apparent enough to demonstrate both that the moon is a sphere and that you're moving in relation to the moon.

tl;dr You need a camera and either a long lens or a telescope that'll hook to it to see how parallax lets you view the moon from different angles. So, the moon always shows one face to Earth. Round Earthers believe it's because, despite the moon being a sphere, it's "tidally locked" to Earth and stuck in that position. Sounds suspicious, eh? Well, Round Earthers also believe we are also on a big sphere, and that sphere is constantly turning. If that's true, we're also shifting in position in relation to the moon. If the moon was a sphere you'd be looking at it from different angles, wouldn't you? Well, turns out you can. If you can take good quality photos of the moon at dawn and dusk you'll see the moon from different angles. If you take a number of different photos over night and string them together you'll be able to see the angular change. With a good view (you'll need a 1000mm equivalent lens or better) the 3D motion is apparent enough to demonstrate both that the moon is a sphere and that you're moving in relation to the moon.

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[–] • 1 pt (edited )

Sounds suspicious, eh?

No. Not even slightly. The moon rotates a a rate equal to it's revolution around the Earth so it's 'tide locked'. The forces of gravity then also cause a wobble. None of this is that difficult to understand. This was stuff that I understood when I was like 10.

If the Earth were flat and the Moon spherical then the movement of the Moon would cause the same 'bottom' of the Moon to be seen everywhere but a different 'side' of the moon as it moved.

If the Moon were also flat the movement of the moon would be extremely odd for us to be able to see the same face at all points.

[–] • 0 pt (edited )

Not quite. The moons orbit is slightly elliptical, so it appears to move among the stars faster when it's nearer to the earth at some times than other times, and slower when it's farther at times. So sometimes the moons relatively steady rotation gets ahead of the revolution at times, and lags behind other times.

Also, OP's image is indeed correct as far as it goes, but what's involved in libration can be seen from one place over the course of a month.