Andromeda is visible from 2.5 million light-years because the light of hundreds of billions of stars blends together. But an Earth-like planet there would be roughly ten billion times fainter than its own star and separated from it by only about 1.3 microarcseconds - Space Daily

Andromeda can be found without a telescope under a sufficiently dark sky, even though its light has travelled about 2.5 million years. That sounds like an argument for astronomical eyesight. It is re…