Which type of telescope has two lenses?

The refracting telescope is the correct answer because it utilizes two lenses to focus light and form an image. The primary lens, known as the objective lens, gathers light and brings it to a focal point, while the secondary lens, called the eyepiece, magnifies the image produced by the objective lens for better viewing. This design is fundamental to refracting telescopes, allowing them to provide clear images of celestial objects.

In comparison, the reflecting telescope uses mirrors instead of lenses to gather and focus light. The Newtonian telescope, which is a type of reflecting telescope, also employs mirrors for the same purpose. Lastly, the catadioptric telescope combines both lenses and mirrors in its construction but does not primarily rely on two lenses like the refracting telescope does. Thus, the defining characteristic of the refracting telescope is its use of a dual lens system, making it distinct from the other types mentioned.