TY - JOUR
T1 - Laboratory demonstration of astrometric compensation using a diffractive pupil
AU - Bendek, Eduardo A.
AU - Guyon, Olivier
AU - Mark Ammons, S.
AU - Belikov, Ruslan
PY - 2013/10
Y1 - 2013/10
N2 - Astrometry is a promising exoplanet detection and characterization technique that can detect earthsize exoplanets if submicroarcsecond precision is achieved. However, instrumentation available today can only reach in the order of 102 microarcseconds, mainly limited by long-term dynamic distortions on wide-field observations. To overcome this problem, we propose the implementation of a diffractive pupil, which has an array of microscopic dots imprinted on the primary mirror coating. The dots create diffractive spikes on the focal plane that are used to calibrate image plane distortions that degrade the astrometric measurement precision. This astrometry technique can be utilized simultaneously with coronagraphy for exhaustive characterization of exoplanets (mass, spectra, orbit). We designed and built an astrometry laboratory to validate the diffractive pupil ability to calibrate distortions and stabilize wide-field astrometric measurements over time. We achieved a precision of 0.0123 px, which represents 42% of the 0.0288 px stability measured for this setup before the calibration. On sky units, this result is equivalent to 3:42 × 10-3λ=D that corresponds to 150 μas for a 2.4 m telescope at 500 nm wavelength. Also, at large field angles the distortion error was reduced by a factor of 5 when the calibration was used, proving its effectiveness for large field of view.We present an astrometry error budget here to explain the source of the residual error observed when the diffractive pupil calibration is used.
AB - Astrometry is a promising exoplanet detection and characterization technique that can detect earthsize exoplanets if submicroarcsecond precision is achieved. However, instrumentation available today can only reach in the order of 102 microarcseconds, mainly limited by long-term dynamic distortions on wide-field observations. To overcome this problem, we propose the implementation of a diffractive pupil, which has an array of microscopic dots imprinted on the primary mirror coating. The dots create diffractive spikes on the focal plane that are used to calibrate image plane distortions that degrade the astrometric measurement precision. This astrometry technique can be utilized simultaneously with coronagraphy for exhaustive characterization of exoplanets (mass, spectra, orbit). We designed and built an astrometry laboratory to validate the diffractive pupil ability to calibrate distortions and stabilize wide-field astrometric measurements over time. We achieved a precision of 0.0123 px, which represents 42% of the 0.0288 px stability measured for this setup before the calibration. On sky units, this result is equivalent to 3:42 × 10-3λ=D that corresponds to 150 μas for a 2.4 m telescope at 500 nm wavelength. Also, at large field angles the distortion error was reduced by a factor of 5 when the calibration was used, proving its effectiveness for large field of view.We present an astrometry error budget here to explain the source of the residual error observed when the diffractive pupil calibration is used.
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U2 - 10.1086/673373
DO - 10.1086/673373
M3 - Article
AN - SCOPUS:84886795453
VL - 125
SP - 1212
EP - 1225
JO - Publications of the Astronomical Society of the Pacific
JF - Publications of the Astronomical Society of the Pacific
SN - 0004-6280
IS - 932
ER -