Asked by Leonard Logan
It is easy to think that – in its captured rotation – the Moon always keeps the same hemisphere turned towards the Earth, resulting in us seeing only 50 per cent of the lunar surface. However, since the Moon’s motion is quite complicated, we are able to see a little way around the east and west limb and over the north and south poles upping the percentage to 59 per cent.
Astronomers call this extra nine per cent of the lunar surface the libration zones, caused by the slightly elongated orbit of the Moon around the Earth, which makes our lunar companion gently wobble in the Earth’s sky. If you take a look at the Moon with a telescope or binoculars, you will notice that observing and even identifying formations in this zone is far from easy, since craters and other such features are foreshortened and seen highly edge-on. While this ‘uncharted territory’ has been photographed in detail, observing it is still a challenge and if you look hard enough you’ll get to see a section of the Moon that not many amateur astronomers and casual lunar observers have seen.
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