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Star Diagonal: Used to change the angle of the light coming out of a telescope, for easier viewing. Herschel Wedge: Similar to a star diagonal with a wedge-shaped unsilvered prism reflector that reduces incoming light by up to 95% for solar viewing. Coma corrector a correcting lens used to reduce coma distortion in fast reflecting telescopes.
The telescope is more a discovery of optical craftsmen than an invention of a scientist. [1] [2] The lens and the properties of refracting and reflecting light had been known since antiquity, and theory on how they worked was developed by ancient Greek philosophers, preserved and expanded on in the medieval Islamic world, and had reached a significantly advanced state by the time of the ...
The reflecting telescope, which uses mirrors to collect and focus light, was invented within a few decades of the first refracting telescope. In the 20th century, many new types of telescopes were invented, including radio telescopes in the 1930s and infrared telescopes in the 1960s.
The history of light therapy can be traced back to ancient Egypt and India, where therapy with natural sunlight was first used to treat leucoderma. [3] In the 1850s, Florence Nightingale's advocacy of exposure to clean air and sunlight for health restoration also contributed to the initial development of light therapy for treatments. [4]
Light path in a meniscus telescope (Maksutov–Cassegrain) Maksutov–Cassegrain telescopes are the most commonly seen design that uses a meniscus corrector, a variant of the Maksutov telescope. It has a silvered "spot" secondary on the corrector, making a long focal length but compact (folded optical path) telescope with a narrow field of view.
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Visible-light astronomy has existed as long as people have been looking up at the night sky, although it has since improved in its observational capabilities since the invention of the telescope, which is commonly credited to Hans Lippershey, a German-Dutch spectacle-maker, [1] although Galileo played a large role in the development and ...
Support for the idea can be found as far back as 2005, when a meta-analysis published in the American Journal of Psychiatry found that light therapy is effective for both SAD and non-seasonal ...