Ok, I'm going to make a proposition to everyone on this forum who identifies themselves as Flat-Earthers.
As the discussions in this topic show, the FE model really doesn't provide an adequate or even simple answer to the question of libration. So I propose this.
Why doesn't Flat Earth Society integrate the idea that the moon and sun are round into their philosophy? If FE is a true scientific idea, it should be aloud to do this.
Allowing the moon and sun to be spherical would simplify things in many ways for the FE community.
1. It would adequately explain the observed effects of libration, and the observed rotation of the sun when viewed through a solar filter.
2. It would explain why the moon and sun never appear spherical, without the need to imply any form of atmospheric distortion or lensing.
3. It would explain the phases of the moon, without the need for the proposed "third body" as dogplatter put it.
4. It could explain tides as caused by the attraction from the moon and the sun, without the need for the earth to tilt about periodically.
All this without touching the basic premise of the Earth's shape.
So how about it FE'ers? Simplify your whole hypothesis and allow celestial bodies to assume a spherical shape. After all, Samuel Rowbotham was just a human, he could have been wrong about them.