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9 December 2004 Kilometer scale primary collector telescopy
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We present an improved model for a spectrographic survey telescope with a kilometer scale diffraction grating collector. Refining the initial public disclosures, the new model quantifies flux collection for telescopes of this type. An option in the new model allows a trade of reduced spectral bandwidth for increased flux collection. We provide experimental evidence to demonstrate an earlier prediction of Ångstrom spectral resolution with relaxed tolerances for grating flatness. This model also posits a kilometer focal length secondary parabolic mirror and details its secondary spectrometer. Terrestrial installations for telescopes of this type can be at the ground level, presenting a near-zero wind profile despite the unprecedented kilometer scale aperture. The secondary, consisting of a parabolic reflector, is mechanically independent of the primary and completely static. The resulting open frame eliminates the need for a secondary spyder and has no obstructions in the active ray path. The grating primary can be combined with zenith tube liquid mirrors to provide full coverage of right ascension and all angles of declination. A folding mirror can be used as adaptive wave front correction. In space-based deployment, the kilometer length primary can be stowed as a membrane and unfurled in orbit using simple inertial forces.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Thomas D. Ditto, Jeffrey Foster Friedman, and Jeffrey T. Baker "Kilometer scale primary collector telescopy", Proc. SPIE 5578, Photonics North 2004: Photonic Applications in Astronomy, Biomedicine, Imaging, Materials Processing, and Education, (9 December 2004);


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