The "Main Mirror" is a crucial component in telescopes, particularly in reflecting telescopes. It is designed to gather and focus light from distant celestial objects, allowing astronomers to observe and study them in detail. The size and shape of the main mirror significantly influence the telescope's ability to capture light and resolve fine details. In large observatories, such as the Hubble Space Telescope or the Keck Observatory, the main mirror can be several meters in diameter. These mirrors are often made of glass or other materials that are polished to a precise shape, ensuring that they can effectively reflect light and produce clear images of stars, planets, and galaxies.