Refraktoren, or refractors, are telescopes that use lenses to gather and focus light. They typically consist of an objective lens at the front and an eyepiece lens at the back. This design allows for clear images of celestial objects, making refractors popular among amateur astronomers and professionals alike. The main advantage of refractors is their ability to produce sharp, high-contrast images with minimal distortion. However, they can be more expensive to manufacture than other types of telescopes, such as reflectors, which use mirrors instead of lenses. Refractors are often used for planetary observation and astrophotography.