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Proceedings Paper

NEAT: a microarcsec astrometric telescope
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Paper Abstract

NEAT, Nearby Exo-Earth Astrometric Telescope is a medium-small telescope ~ 1m in diameter that is designed to make ultra precise < 1 uas (microarcsec) astrometric measurements of nearby stars in a ~ 1hr observation. Four major error sources prevent normal space telescopes from obtaining accuracies close to 1 uas. Even with a small 1m telescope, photon noise is usually not a problem for the bright nearby target stars. But in general, the reference stars are much fainter. Typically a field of view of ~0.5 deg dia is needed to obtain enough bright reference stars. The NEAT concept uses a very simple but unusual design to avoid optically induced astrometric errors. The third source of error is the accuracy and stability of the focal plane. A 1uas error over a ~2000 arcsec field of view implies the focal plane is accurate or at least stable to 5 parts in 1010 over the lifetime of the mission (~5yrs). The 4th class of error has to do with our knowledge of the PSF and how that PSF is sampled by an imperfect detector. A Nyquist sampled focal plane would have > 2 pixels per λ/D, and centroiding to 1uas means centroiding to 10-5 pixels. This paper describes the mission concept, and an overview of the technology needed to perform 1uas astrometry with a small telescope, and how we overcome problems 1 and 2. A companion paper will describe the technical progress we've made in solving problems 3 and 4.

Paper Details

Date Published: 15 September 2011
PDF: 7 pages
Proc. SPIE 8151, Techniques and Instrumentation for Detection of Exoplanets V, 81510V (15 September 2011); doi: 10.1117/12.894481
Show Author Affiliations
M. Shao, Jet Propulsion Lab. (United States)
B. Nemati, Jet Propulsion Lab. (United States)
C. Zhai, Jet Propulsion Lab. (United States)
R. Goullioud, Jet Propulsion Lab. (United States)
F. Malbet, IPAG (France)
A. Leger, Univ. Paris (France)


Published in SPIE Proceedings Vol. 8151:
Techniques and Instrumentation for Detection of Exoplanets V
Stuart Shaklan, Editor(s)

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