Question: How does a telescope work?

Sarah Martin answered on 20 Jun 2012:

Hi meg!

Two pieces in a telescope help make things far away look bigger:
The objective lens collects lots of light from a distant object and brings that light, or image, to a point or focus.
An eyepiece lens takes the bright light from the focus of the objective lens and “spreads it out” (magnifies it) to take up a large portion of the retina in your eye. This is the same principle that a magnifying glass (lens) uses; it takes a small image on the paper and spreads it out over the retina of your eye so that it looks big.
When you combine the objective lens or primary mirror with the eyepiece, you have a telescope! Here’s a diagram of the lenses:

You could build one yourself out of magnifying lenses!

🙂 Sarah