The concept of lunar libration proves that the Moon is not a flat metal disc, as some flat guys believe. When confronted with images showing this effect, the standard flat response is to say "that's an animated computer representation, not a real photo".
Well here's some photos showing the effect, taken by me from my back garden. I am of course still aware that the flat guys don't accept photos as evidence of anything, however now they can no longer say the only thing we show of libration is a computer animation.
These images show the Moon taken firstly on 29th January this year, and secondly on 24th April this year. The red arrow shows the position of the crater Endymion.
Note how much closer this crater is to the edge of the Moon in the first picture than it is in the second. This is because the second picture depicts the Moon tlited southwards, so we get a better view of its northern side.
These pictures were taken with exactly the same camera, from the same location, and are at the same magnification. Resolution of the image is roughly 40km per pixel (these have been blown up 200% to make it easier to see though.)