The northern and southern 'continous viewing zone' is the angle from north pole that you can see continualy without the sun/earth getting in the way, it just depends on the orbit. The instruments generally don't observe for very long because of cosmic rays, it's better to stack shorter exposures.Oh cool! I didn't know that. That's a really interesting point. Has Hubble always had that capability or was that added in one of the repair/service missions? If I recall correctly, the WFPC can't do that.
Ok, I was just making it clear that the Earth is never in the sky from the back side of the moon but the sun is half the time.I was just suggesting that night on the far side of the Moon is much darker than night on Earth, and no human-generated light pollution would affect the telescope.
The best place to put a telescope for a good view is at L2, the Lagrange point directly out along on a line from the sun through the Earth.