Why does the moon appear larger at horizon?

Answer: Moon illusion from context cues

Moon illusion from context cues ✓ — Correct! This is the moon illusion—a perceptual phenomenon, not optical. The moon's actual size on your retina doesn't change. When near the horizon, surrounding objects (trees, buildings) provide size-comparison context, making the moon seem larger. When high overhead with no references, it appears smaller. Your brain's size-constancy mechanism is fooled!

Atmosphere magnifies at horizon — Wrong. Atmosphere doesn't magnify the moon. This is a perceptual illusion—your brain interprets the moon as larger at the horizon due to surrounding context references.

Eye lens adjusts differently — Wrong. Eye lens adjusts the same. The moon illusion is psychological—context cues at the horizon make your brain perceive the moon as larger.