A telescope is an important tool for astronomy. The telescope gathers and focuses light. Telescopes make things seem bigger and brighter. Galileo was the first person to use a telescope for astronomy, but he did not invent them. Telescopes not used for astronomy can be named transits, spotting scopes, monoculars, binoculars, camera lenses, or spyglasses.

The word "telescope" is usually used for light your eyes can see, but there are telescopes for "invisible" light. Infrared telescopes look like normal telescopes, but have to be kept cold since infrared light is heat. Radio telescopes are like radio antennas, usually shaped like large dishes. X-ray and gamma-ray telescopes have a problem because the rays go through most metals and glasses. To solve this problem, they are shaped like a bunch of rings inside each other. The first telescope was invented in the Netherlands in 1608.