Binoculars
Videos
Binoculars or field glasses are two refracting telescopes mounted side-by-side and aligned to point in the same direction, allowing the viewer to use both eyes when viewing distant objects. Most binoc
8×42 roof prism binoculars with rainguard and opened tethered lens caps
WW1 era Galilean type binoculars
Porro prism binoculars, with distinctive eyepiece/objective axis offset
Binoculars diagram showing an Abbe–Koenig roof prism design
Refracting telescope
Videos
A refracting telescope is a type of optical telescope that uses a lens as its objective to form an image. The refracting telescope design was originally used in spyglasses and astronomical telescopes
Binoculars
…Binoculars or field glasses are two refracting telescopes mounted side-by-side and aligned to point in the same direction, allowing the viewer to use both eyes (binocular vision) when viewing distant objects…
A 200 mm diameter refracting telescope at the Poznań Observatory
Engraved illustration of a 46 m (150 ft) focal length Keplerian astronomical refracting telescope built by Johannes Hevelius.
Alvan Clark polishes the big Yerkes achromatic objective lens, over 1 meter (100 cm) across (1896).
This 12-inch (30 cm) refractor is mounted in a dome on a mount that matches the Earth's rotation.