How does a telescope work?

Telescopes use mirrors or lenses to gather and focus light from distant objects, allowing astronomers to see them:
Light collection
The size of a telescope’s main mirror or lens determines how much light it can collect. Larger mirrors or lenses can collect more light and detect fainter objects.
Light focusing
The shape of the mirror or lens concentrates light into a single point, called the focal point.
Image magnification
When viewed through a telescope’s eyepiece or camera, the concentrated image appears magnified.
There are several types of telescopes, including:
Refracting telescopes
Use lenses to bend, or refract, light. The first telescopes were refracting telescopes, and many backyard telescopes today are still refracting.
Reflecting telescopes
Use mirrors to collect and focus light. Reflecting telescopes are ideal for space because large mirrors can be made lighter and thinner than lenses of the same size.
Catadioptric telescopes
Combine lenses and mirrors to focus light. These telescopes are typically compact and easy to transport and handle.