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P. Gorenstein (Harvard-Smithsonian Center for Astrophysics)
Larger versions of diffractive and refractive X-ray devices currently in use at synchrotron facilities for X-ray microscopy are potentially an entire new class of X-ray optics for astronomy. These elements can be configured as either high angular resolution telescopes for imaging, or high throughput concentrators for X-ray timing and moderate resolution spectroscopy with cryogenic or solid state detectors. They are theoretically capable of providing very high angular resolution on a level than can either complement or be an alternative to X-ray interferometry for imaging a black hole during the Beyond Einstein era. They also themselves can be configured for X-ray interferometry. As they are normal incidence devices, which operate in transmission, compared to grazing incidence telescopes they are extremely lightweight per unit area and the surface smoothness is much less critical. However, two major impediments must be overcome before devices composed of diffractive-refractive elements can be applied. They are chromatic aberration and like X-ray interferometry the need to accommodate extremely long focal lengths and separations between components with precision formation flying between multiple spacecraft. The latter requires the development of new technology for mission operations. We describe methods for dealing with chromatic aberration including a technique described by Leon Van Speybroeck.
Bulletin of the American Astronomical Society,
35#2
© 2003. The American Astronomical Soceity.