teleskop

A teleskop is an optical instrument designed to observe distant objects by collecting light and forming a magnified image. It allows detailed study of celestial bodies and, in some variants, serves as a tool for navigation and terrestrial observation.

The earliest practical telescopes were developed in the early 17th century. Hans Lippershey, Zacharias Janssen and others contributed to the invention; Galileo improved the design and used it to observe the moons of Jupiter and the phases of Venus. Sir Isaac Newton built the first practical reflecting telescope in 1668 to reduce chromatic aberration. Through the 18th to 20th centuries, instrumentation and optics advanced, enabling larger apertures and higher magnifications.

Most common types are optical telescopes, which use lenses (refractors) or mirrors (reflectors) to form an image, or catadioptric designs that combine both. In addition, radio telescopes and infrared or ultraviolet telescopes observe non-visible wavelengths. Modern telescopes can be ground-based or space-based.

Key components include the objective lens or primary mirror, a secondary mirror and eyepiece, a telescope tube, and a mounting system (alt-azimuth or equatorial). The magnification is the focal length of the objective divided by the focal length of the eyepiece. The light-gathering power grows with the square of the aperture, and the resolving power improves with aperture and with shorter wavelengths. Telescopes may incorporate adaptive optics or interferometric techniques to counteract atmospheric distortion.

Contemporary large optical telescopes on Earth, such as the Very Large Telescope and Keck, use giant mirrors and sophisticated mounts. Space telescopes, including the Hubble Space Telescope and the James Webb Space Telescope, operate above Earth's atmosphere to achieve higher clarity. Other wavelengths use dedicated facilities like radio dishes and infrared arrays.

Teleskops are essential tools in astronomy, astrophysics, education, and increasingly in citizen science. They contribute to imaging, spectroscopy, and time-domain observations, expanding our understanding of the universe.