A cosmic telescope is a concept in astrophysics that involves using massive celestial objects, such as galaxies or galaxy clusters, as natural lenses to magnify and study distant objects in the universe. This phenomena, known as gravitational lensing, occurs when the gravitational field of a massive object bends and magnifies light from objects located behind it, essentially acting as a "telescope" to observe those distant objects. Cosmic telescopes have been used by astronomers to study a variety of objects, such as distant galaxies, quasars, and supernovae, providing valuable insights into the early universe, dark matter distribution, and the nature of dark energy. By leveraging the magnifying power of these natural lenses, researchers are able to observe and study objects that would otherwise be too faint or distant to detect with conventional telescopes. Overall, cosmic telescopes offer a unique and powerful tool for exploring the universe and advancing our understanding of its underlying structure and dynamics.