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visible light can be bounced of a curved mirror and directed to a focal point

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x-ray light, however, will be absorbed by the mirror

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will not bounce back to the focal point

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X-ray photons penetrate into the mirror in much the same way that bullets slam into a wall

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likewise, just as bullets ricochet when they hit a wall at a grazing angle, so too will X-rays ricochet off mirrors

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therefore X-ray telescopes must be constructed very different from optical telescopes

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mirrors have to be precisely shaped and aligned nearly parallel to incoming X-rays

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they look more like barrels than the familiar dish shape of optical telescopes

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x-ray telescope

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designed to observe remote objects in the X-ray spectrum

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the Earth's atmosphere absorbs X-rays, X-ray observatories

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must therefore be mounted on high altitude rockets or artificial satellites in order to get above the Earth's atmosphere

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mirrors, detectors, and electronics that convey the information back to Earth must be able to

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withstand the rigors of a rocket launch

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operate in the hostile environment of space

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NASA's Chandra X-ray Observatory

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most important X-ray astronomy mission to date

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launched on July 23, 1999

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four sets of nested mirrors

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the mirror surface was coated with iridium, a material more reflective than gold

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Sco X-1 (Scorpius X-1)

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roughly 9000 light years away in the constellation Scorpius

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aside from the Sun, it is the strongest apparent source of X-rays in the sky

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is associated with an optically visible star, V818 Scorpii