A refractor telescope is an optical telescope that uses lenses in each ends of the telescope to bend and refract light to form an image. The refraction of the parallel light beams causes them to gather in a focus point and those beams that were not parallel will gather on the focal plane. Therefore the user of the refractor telescope can see the distant object under examination more brightly, clearly and/or larger than it would be otherwise possible.

There are many similarities between refractor telescopes and microscopes. A typical refractor telescope has usually two lenses- an objective lens and an eyepiece lens. The refractor telescope uses convex glass lenses on both cases, which are thicker in the middle than in the edges. The same kinds of lenses are usually used in photo cameras to gather light to one place to be able to form an image. The refractor telescope also consists of a tube that is usually made out of metal, plastic or wood.

The refractor telescope is usually used to look at distance objects, like the stars, planets or anything else that is far away.  These objects can be seen because when light goes through the objective lens, it converges and generate a real image in the center of the tube close to the eyepiece lens, which increases the size of the image making it seem larger than it is in reality. That is how a refractor telescope works.