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The Reflection of Optical and X-Ray Platforms Striking Conventional Telescope
Mirror
How do X-ray telescopes differ from optical telescopes?
(java enhanced)
X-rays do not reflect off mirrors the same way that visible light does. Because
of their high-energy, X-ray photons that strike a mirror directly will penetrate
into the mirror in much the same way that bullets aimed directly at a surface
will bury themselves in it. Likewise, just as a bullets can ricochet off a
surface when they hit it at a grazing angle, so too will X-rays ricochet off
mirrors if they hit at very shallow angles, like a stone skipping across the
surface of a pond. These properties mean that X-ray telescopes must be very
different from optical telescopes.
The Chandra mirrors look more like barrels than the familiar dish shape of
optical telescopes. Four 'mirror' shells are nested inside one another to
increase the total reflecting are of the telescope. The inner, reflecting
surfaces of the mirrors have to be precisely shaped, and aligned nearly parallel
to the incoming X-rays. The mirrors focus X-ray photons onto state-of-the-art
detectors which record position, and in some cases the energy, of the photons.
These X-ray data are then analyzed and reconstructed into images of the celestial
objects that produce the emissions.
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