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Real-time speckle sensing and suppression with project 1640 at Palomar

Vasisht, Gautam and Cady, Eric and Zhai, Chengxing and Lockhart, Thomas and Oppenheimer, Ben (2014) Real-time speckle sensing and suppression with project 1640 at Palomar. In: Adaptive Optics Systems IV. Proceedings of SPIE. No.9148. Society of Photo-optical Instrumentation Engineers (SPIE) , Bellingham, WA, Art. No. 914822. ISBN 9780819496164.

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Palomar’s Project 1640 (P1640) is the first stellar coronagraph to regularly use active coronagraphic wavefront control (CWFC). For this it has a hierarchy of offset wavefront sensors (WFS), the most important of which is the higher-order WFS (called CAL), which tracks quasi-static modes between 2-35 cycles-per-aperture. The wavefront is measured in the coronagraph at 0.01 Hz rates, providing slope targets to the upstream Palm 3000 adaptive optics (AO) system. The CWFC handles all non-common path distortions up to the coronagraphic focal plane mask, but does not sense second order modes between the WFSs and the science integral field unit (IFU); these modes determine the system’s current limit. We have two CWFC operating modes: (1) P-mode, where we only control phases, generating double-sided darkholes by correcting to the largest controllable spatial frequencies, and (2) E-mode, where we can control amplitudes and phases, generating single-sided dark-holes in specified regions-of-interest. We describe the performance and limitations of both these modes, and discuss the improvements we are considering going forward.

Item Type:Book Section
Related URLs:
URLURL TypeDescription
Vasisht, Gautam0000-0002-1871-6264
Cady, Eric0000-0002-8789-2931
Zhai, Chengxing0000-0002-0291-4522
Oppenheimer, Ben0000-0001-7130-7681
Additional Information:© 2014 Society of Photo-Optical Instrumentation Engineers (SPIE).
Subject Keywords:Exoplanets, coronagraphy, interferometry
Series Name:Proceedings of SPIE
Issue or Number:9148
Record Number:CaltechAUTHORS:20180713-140028642
Persistent URL:
Official Citation:Gautam Vasisht, Eric Cady, Chengxing Zhai, Thomas Lockhart, Ben Oppenheimer, "Realtime speckle sensing and suppression with project 1640 at Palomar", Proc. SPIE 9148, Adaptive Optics Systems IV, 914822 (22 August 2014); doi: 10.1117/12.2056591;
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:87842
Deposited By: George Porter
Deposited On:13 Jul 2018 22:54
Last Modified:09 Mar 2020 13:19

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