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Proceedings Paper

Estimate low- and high-order wavefront using P1640 calibrator measurements
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Paper Abstract

P1640 high contrast imaging system on the Palomar 200 inch Telescope consists of an apodized-pupil Lyot coronagraph, the PALM-3000 adaptive optics (P3K-AO), and P1640 Calibrator (CAL). Science images are recorded by an integral field spectrograph covering J-H bands for detecting and characterizing stellar companions. With aberrations from atmosphere corrected by the P3K-AO, instrument performance is limited mainly by the quasi-static speckles due to noncommon path wavefront aberrations for the light to propagate to the P3K-AO wavefront sensor and to the coronagraph mask. The non-common path wavefront aberrations are sensed by CAL, which measures the post-coronagraph E-field using interferometry, and can be effectively corrected by offsetting the P3K-AO deformable mirror target position accordingly. Previously, we have demonstrated using CAL measurements to correct high order wavefront aberrations, which is directly connected to the static speckles in the image plane. Low order wavefront, on the other hand, usually of larger amplitudes, causes light to leak through the coronagraph making the whole image plane brighter. Knowledge error in low order wavefront aberrations can also affect the estimation of the high order wavefront. Even though, CAL is designed to sense efficiently high order wavefront aberrations, the low order wavefront front can be inferred with less sensitivity. Here, we describe our method for estimating both low and high order wavefront aberrations using CAL measurements by propagating the post-coronagraph E-field to a pupil before the coronagraph. We present the results from applying this method to both simulated and experiment data.

Paper Details

Date Published: 26 September 2013
PDF: 9 pages
Proc. SPIE 8864, Techniques and Instrumentation for Detection of Exoplanets VI, 88640L (26 September 2013); doi: 10.1117/12.2024754
Show Author Affiliations
C. Zhai, Jet Propulsion Lab. (United States)
G. Vasisht, Jet Propulsion Lab. (United States)
M. Shao, Jet Propulsion Lab. (United States)
T. Lockhart, Jet Propulsion Lab. (United States)
E. Cady, Jet Propulsion Lab. (United States)
B. Oppenheimer, American Museum of Natural History (United States)
R. Burruss, Jet Propulsion Lab. (United States)
J. Roberts, Jet Propulsion Lab. (United States)
C. Beichman, California Institute of Technology (United States)
D. Brenner, American Museum of Natural History (United States)
J. Crepp, Univ. of Notre Dame (United States)
R. Dekany, California Institute of Technology (United States)
L. Hillenbrand, California Institute of Technology (United States)
S. Hinkley, California Institute of Technology (United States)
I. Parry, Cambridge Univ. (United Kingdom)
L. Pueyo, Johns Hopkins Univ. (United States)
E. Rice, American Museum of Natural History (United States)
L. C. Roberts, Jet Propulsion Lab. (United States)
A. Sivaramakrishnan, Space Telescope Science Institute (United States)
R. Soummer, Johns Hopkins Univ. (United States)
H. Tang, Jet Propulsion Lab. (United States)
F. Vescelus, Jet Propulsion Lab. (United States)
K. Wallace, Jet Propulsion Lab. (United States)
N. Zimmerman, Max-Planck-Institut für Astronomie (Germany)

Published in SPIE Proceedings Vol. 8864:
Techniques and Instrumentation for Detection of Exoplanets VI
Stuart Shaklan, Editor(s)

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