What physical phenomenon must trustworthy solar position calculators often incorporate for accurate apparent position readings near the horizon?

Answer

Atmospheric refraction

Trustworthy sources often incorporate atmospheric corrections because atmospheric refraction—the bending of light as it passes through the atmosphere—makes the Sun appear slightly higher than its true geometric position, especially near the horizon.

What physical phenomenon must trustworthy solar position calculators often incorporate for accurate apparent position readings near the horizon?
locationsunastronomyCurrentPosition