Kamin using his telescope.
Cochrane's telescope.
The Enterprise-E through a telescope.
A telescope is an optical device consisting of variable combinations of lenses and mirrors that focus light, allowing for viewing of distant objects. Widely used in the fields of astronomy and surveying. Early Human configurations of the telescope were constructed by Galileo Galilei.
Kamin built a telescope on Kataan that he and his daughter Meribor used often. (TNG: "The Inner Light")
Zefram Cochrane used a reflecting telescope to view the Enterprise-E in orbit around Earth in 2063. (Star Trek: First Contact)
In 2154, the Syrranites used telescopes to discover three Vulcan cruisers over the Forge, ready to attack their compound in the T'Karath Sanctuary. (ENT: "Awakening")