As others have pointed out, this was considered. Here is the relevant excerpt from the paper: > To avoid an articulating mount, the telescope would be placed a

As others have pointed out, this was considered. Here is the relevant excerpt from the paper: > To avoid an articulating mount, the telescope would be placed at the lunar pole, constantly pointing at the zenith. [...] The limit on exposure time is then given by the precession of the moon, and is of the order of several days. This can only be extended by the addition of some active tracking facility, for example a moving prime focus platform.