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.