100 miles is sufficient to cancel out any interplay of light rays.
People who live on the sea coast always see the mast of the ship before they see the ship.
“100 miles is sufficient to cancel out any interplay of light rays.”
There is no distance limit on atmospheric refraction. In fact, celestial bodies, which are many times further away than any object you would be sighting on the surface of the earth, are always affected by refraction when they are near the horizon, to one degree or another. For example, when you see the sun touching the horizon at sunset, it has actually already sunk below the horizon.