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Proceedings Paper

Kilometer-scale primary objective telescope with no moving parts
Author(s): Thomas Ditto
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Paper Abstract

he author proposes the use of a diffraction grating as a primary collector in a very large ground-based telescope. The grating is to be placed at grazing exodus relative to a secondary receiver and will have considerable length relative to width. Collector areas of square kilometers are being considered. Large collectors pose problems for ordinary telescopes, but with the proposed telescope, the rotation of the earth is the only requisite motion. Other than the earth itself, there are no moving parts. In the course of a night's observation, a plurality of stars within a narrow band of right ascension would yield detailed spectra. We anticipate that while acquiring the spectra of a star, the instrument would also acquire the spectra of any planetary system around it, because the high inherent resolving power of the instrument can measure subtle Doppler shifts, and the collecting area is sufficiently large to detect spectra from planets in the full glare of the star that illuminates them. Where signature spectra are available, planets can by typed, including earth-like planets which can be distinguished by their unique spectra and their implied surface temperature as inferred from orbit diameter. Our study investigates several grating arrangements, types and efficiencies including some using reflection gratings and one with a transmission grating in an evanescent mode. We explore options for grating fabrication and mounting

Paper Details

Date Published: 4 February 2003
PDF: 10 pages
Proc. SPIE 4837, Large Ground-based Telescopes, (4 February 2003); doi: 10.1117/12.458208
Show Author Affiliations
Thomas Ditto, DeWitt Brothers Tool Co., Inc. (United States)


Published in SPIE Proceedings Vol. 4837:
Large Ground-based Telescopes
Jacobus M. Oschmann; Larry M. Stepp, Editor(s)

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