aside from the sun, the most notable object in neptune's sky is its large moon triton, which would appear slightly smaller than a full moon on earth. it moves more swiftly than our moon. the smaller moon proteus would show a disk about half the size of the full moon. an alignment of the inner moons would likely produce a spectacular sight. neptune's large outer satellite, nereid, is not large enough to appear as a disk from neptune, and is not noticeable in the sky. the other irregular outer moons would not be visible to the naked eye.