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The devices, called bioptic telescopic glasses, can help patients resume reading, recognizing faces across a room, watching TV, playing cards, in some cases even driving, Palmer said. But for ...
Bioptics, also known as a bioptic in the singular, and sometimes more formally termed a bioptic telescope, is a term for a pair of vision-enhancement lenses. They magnify between two and six times, and are used to improve distance vision for those with severely impaired eyesight, especially those with albinism .
glass mirror reflector: First large Ritchey-Chrétien: Flagstaff, Arizona, USA (Washington, D.C. until 1955) 1934 Plaskett telescope [7] 1.83 m: 72" glass mirror reflector: Designed as world's largest but beaten by the 100-inch Hooker telescope: Dominion Astrophysical Observatory, Canada, USA: 1918 Hooker Telescope: 2.54 m: 100" glass mirror ...
The main material used early on for reflecting telescope mirrors was speculum metal, which reflected only about two-thirds of the incident light, and which tarnished, requiring maintenance. Two-element refracting telescopes were extensively used in 19th century observatories despite their smaller apertures than metal, and later glass, mirror ...
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. Most binoculars are sized to be held using both hands, although sizes vary widely from opera glasses to large pedestal-mounted military ...
This is a list of large optical telescopes. For telescopes larger than 3 meters in aperture see List of largest optical reflecting telescopes . This list combines large or expensive reflecting telescopes from any era, as what constitutes famous reflector has changed over time.
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