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Proceedings Paper

A first order wavefront estimation algorithm for P1640 calibrator
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Paper Abstract

P1640 calibrator is a wavefront sensor working with the P1640 coronagraph and the Palomar 3000 actuator adaptive optics system (P3K) at the Palomar 200 inch Hale telescope. It measures the wavefront by interfering post-coronagraph light with a reference beam formed by low-pass filtering the blocked light from the coronagraph focal plane mask. The P1640 instrument has a similar architecture to the Gemini Planet Imager (GPI) and its performance is currently limited by the quasi-static speckles due to non-common path wavefront errors, which comes from the non-common path for the light to arrive at the AO wavefront sensor and the coronagraph mask. By measuring the wavefront after the coronagraph mask, the non-common path wavefront error can be estimated and corrected by feeding back the error signal to the deformable mirror (DM) of the P3K AO system. Here, we present a first order wavefront estimation algorithm and an instrument calibration scheme used in experiments done recently at Palomar observatory. We calibrate the P1640 calibrator by measuring its responses to poking DM actuators with a sparse checkerboard pattern at different amplitudes. The calibration yields a complex normalization factor for wavefront estimation and establishes the registration of the DM actuators at the pupil camera of the P1640 calibrator, necessary for wavefront correction. Improvement of imaging quality after feeding back the wavefront correction to the AO system demonstrated the efficacy of the algorithm.

Paper Details

Date Published: 13 September 2012
PDF: 12 pages
Proc. SPIE 8447, Adaptive Optics Systems III, 84476W (13 September 2012); doi: 10.1117/12.927015
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, California Institute of Technology (United States)
R. Dekany, California Institute of Technology (United States)
S. Hinkley, California Institute of Technology (United States)
L. Hillenbrand, California Institute of Technology (United States)
E. R. Ligon, Jet Propulsion Lab. (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 Jr., Jet Propulsion Lab. (United States)
A. Sivaramakrishnan, Space Telescope Science Institute (United States)
R. Soummer, Johns Hopkins Univ. (United States)
F. Vescelus, Jet Propulsion Lab. (United States)
K. Wallace, Jet Propulsion Lab. (United States)
N. Zimmerman, Max Planck Institute for Astronomy (Germany)

Published in SPIE Proceedings Vol. 8447:
Adaptive Optics Systems III
Brent L. Ellerbroek; Enrico Marchetti; Jean-Pierre Véran, Editor(s)

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