The primary tool used by astronomers is the telescope. Telescopes come in various types, including optical, radio, and infrared, each designed to observe celestial objects in different wavelengths of light. Optical telescopes use lenses or mirrors to magnify and resolve distant stars, planets, and galaxies, while radio telescopes detect radio waves emitted by cosmic phenomena. By utilizing these instruments, astronomers can analyze the universe's structure, composition, and behavior, leading to groundbreaking discoveries. The development of telescopes has revolutionized our understanding of astronomy and allowed for deeper exploration into the cosmos.