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Keck Observatory Galileo's telescopes refractor at Lick Observatory focal length of a lens refracting telescope telescope at Birr Castle concave mirror Newton's reflecting telescope Cassegrain reflector Schmidt telescope
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telescope summary
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View of the Andromeda Galaxy (Messier 31, M31).
Astronomy and Space Quiz
Nicolaus Copernicus. Nicolas Copernicus (1473-1543) Polish astronomer. In 1543 he published, forward proof of a Heliocentric (sun centered) universe. Coloured stipple engraving published London 1802. De revolutionibus orbium coelestium libri vi.
All About Astronomy
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Infinite space background with silhouette of telescope. This image elements furnished by NASA.
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Shadow of a man holding large knife in his hand inside of some dark, spooky buiding
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Statue of Liberty in front of the skyline of Manhattan, New York City, New York.
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The Titanic. (disasters, ships)
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Paul Revere. "The bloody massacre perpetrated in King Street Boston on March 5th 1770 by a party of the 29th Regt.," engraved by Paul Revere. Boston Massacre.
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Periodical Cicada, Adult, Magicicada spp. Requires 17 years to complete development. Nymph splits its skin, and transforms into an adult. Feeds on sap of tree roots. Northern Illinois Brood. This brood is the largest emergence of cicadas anywhere
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earthquake. Heavily damaged school in the town of Yingxiu after a major earthquake struck China's Sichuan Province on May 12, 2008.
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Communism - mosaic hammer and sickle with star on the Pavilion of Ukraine at the All Russia Exhibition Centre (also known as VDNKh) in Moscow. Communist symbol of the former Soviet Union. USSR
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Reflectors are used not only to examine the visible region of the electromagnetic spectrum but also to explore both the shorter- and longer-wavelength regions adjacent to it (i.e., the ultraviolet and the infrared). The name of this type of instrument is derived from the fact that the primary mirror reflects the light back to a focus instead of refracting it. The primary mirror usually has a concave spherical or parabolic shape, and, as it reflects the light, it inverts the image at the focal plane. The diagram illustrates the principle of a concave reflecting mirror. The formulas for resolving power, ...(100 of 6033 words)

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