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Proceedings Paper

Optimized wide-field survey telescope using adaptive optics
Author(s): Bernhard Rainer Brandl; Richard G. Dekany; Riccardo Giovanelli
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Paper Abstract

We describe a new technique for ground-based telescopic surveys that can deliver a wide field of view and nearly diffraction-limited image quality. We discuss a very low cost, yet sensitive and efficient, concept to perform science previously considered from space. For ground-based telescopes with small D/r0 (aperture over turbulence cell diameter) a significant improvement in point source sensitivity can be achieved with tip-tilt correction only. However, the solid angle over which image motion is constant is typically less than an arcminute. To achieve tip-tilt correction over a larger field we propose to use a high order adaptive optics system where one pupil sub-aperture now corresponds to one isokinetic patch. The high order deformable mirror is conjugated to an atmospheric height where the tip-tilt "beams" separate from each other while the overall tip-tilt can be taken out with a tip-tilt secondary mirror conjugated to low height. One source per square arcminute with V ≤ 18m is required for the determination of the image motion, allowing a sky coverage of more than 50%. The improvement over seeing limited observations is maximal at D/r0 ≈ 4 with a S/N improvement of a factor of four. An inexpensive system with 500 actuators can correct a field of view of 0.4 × 0.4 deg2. It is thus well-suited for searches of point sources, e.g. high-z SN Ia or other transient phenomena.

Paper Details

Date Published: 24 December 2002
PDF: 9 pages
Proc. SPIE 4836, Survey and Other Telescope Technologies and Discoveries, (24 December 2002); doi: 10.1117/12.457295
Show Author Affiliations
Bernhard Rainer Brandl, Cornell Univ. (United States)
Richard G. Dekany, California Institute of Technology (United States)
Riccardo Giovanelli, Cornell Univ. (United States)

Published in SPIE Proceedings Vol. 4836:
Survey and Other Telescope Technologies and Discoveries
J. Anthony Tyson; Sidney Wolff, Editor(s)

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