Mammoth Memory

Concave lens use – Galileo's telescope

In 1609, Galileo became the first person to study the heavens using a telescope. His first telescope was only 8x magnification. But that year he also developed a 20x magnification one which he used to study the moon and planets.

Galileo used a telescope that was made up of just a convex lens and a concave lens. Far more powerful telescopes were developed using two convex lenses in a line (please see Mammoth Memory convex lenses and their uses).

Below is a section through and ray diagram of Galileo's telescopes:

Cut away ray diagram of Galileo's telescope

The convex lens collected and converged the light. The concave lens made the light parallel again.

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