What type of telescope is a Newtonian telescope?

A Newtonian telescope is classified as a reflecting telescope that employs a curved mirror to gather and focus light. This design was developed by Sir Isaac Newton in the 17th century and is characterized by its use of a primary mirror that reflects light to a focal point. The light is further directed to an eyepiece via a secondary mirror, which is positioned at a 45-degree angle to the primary mirror. This innovative design allows for a compact structure compared to earlier telescopes and effectively eliminates chromatic aberration, a common issue with refracting telescopes that utilize lenses.

While refracting telescopes rely on lenses to bend light, and catadioptric telescopes utilize both lenses and mirrors, the Newtonian telescope's exclusive use of mirrors for light collection and focusing identifies it distinctly as a reflecting telescope. Additionally, although the telescope does magnify objects like stars, this characteristic alone does not define its type, as many optical instruments possess this capability.