What mechanism is fundamentally employed in a refracting telescope like Galileo's?

Answer

Refraction, the bending of light as it passes through lenses

The technology employed by Galileo was based on refraction, which is the physical process of light bending as it passes from one medium (air) to another (glass) through the lenses.

What mechanism is fundamentally employed in a refracting telescope like Galileo's?
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