Catadioptric telescopes are optical instruments that combine lenses and mirrors to gather and focus light. This design allows for a compact structure while providing high-quality images. They are popular among amateur astronomers for their versatility and ease of use. These telescopes typically feature a primary mirror and a secondary mirror, along with a corrector lens. This combination helps to reduce optical aberrations and improve image clarity. Schmidt-Cassegrain and Maksutov-Cassegrain are two common types of catadioptric telescopes, each offering unique advantages for observing celestial objects.