Telescope design involves creating instruments that gather and magnify light from distant objects in space. The two main types of telescopes are refractors, which use lenses to bend light, and reflectors, which use mirrors to collect and focus light. Each design has its advantages, such as refractors providing clearer images and reflectors being more cost-effective for larger apertures. Key components of telescope design include the aperture, which determines the amount of light collected, and the focal length, which affects magnification. Additional features like mounts and eyepieces also play a crucial role in usability and image quality. Notable telescopes, such as the Hubble Space Telescope, exemplify advanced design principles.