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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents



ID: 660575.0, MPI für Astronomie / Publikationen_mpia
A first order wavefront estimation algorithm for P1640 calibrator
Authors:Zhai, C.; Vasisht, G.; Shao, M.; Lockhart, T.; Cady, E.; Oppenheimer, B.; Burruss, R.; Roberts, J.; Beichman, C.; Brenner, D.; Crepp, J.; Dekany, R.; Hinkley, S.; Hillenbrand, L.; Ligon, E. R.; Parry, I.; Pueyo, L.; Rice, E.; Roberts, L. C.; Sivaramakrishnan, A.; Soummer, R.; Vescelus, F.; Wallace, K.; Zimmerman, N.
Publisher:SPIE
Date of Publication (YYYY-MM-DD):2012
Title of Proceedings:Adaptive Optics Systems III
Start Page:id. 84476W-84476W
End Page:12
Volume (in Series):8447
Name of Conference/Meeting:Adaptive Optics Systems III
Audience:Not Specified
Abstract / Description: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.
Comment of the Author/Creator:Date: 2012, July 1, 2012
External Publication Status:published
Document Type:Conference-Paper
Communicated by:N. N.
Affiliations:MPI für Astronomie
Identifiers:URL:http://cdsads.u-strasbg.fr/abs/2012SPIE.8447E..6WZ
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