Icon class icon_class fas fa-quote-left icon_class_computed fas fa-quote-left Related content The first known practical telescopes were refracting telescopes Focus BDD for block RefractingTelescope Source Wikipedia Copyright information Text from Wikipedia and Wiktionary web pages quoted for educational purposes is subject to the Wikipedia Creative Commons Attribution ShareAlike Licence Snippet kind INFO Keywords telescope optical telescope astronomy Previous snippet The first known practical telescopes were refracting telescopes invented in the Netherlands at the beginning of the 17th century, by using glass lenses. Full quote They were used for both terrestrial applications and astronomy. URL https://en.wikipedia.org/wiki/Telescope Next snippet Related snippets A telescope is an optical instrument using lenses, curved mirrors [DISPUTED], or a combination of both to observe distant objects ... The word telescope now refers to a wide range of instruments capable of detecting different regions of the electromagnetic spectrum, and in some cases other types of detectors. The first known practical telescopes were refracting telescopes invented in the Netherlands at the beginning of the 17th century, by using glass lenses. Related snippets (backlinks) Visit also Visit also (backlinks) Flags