Realtime speckle sensing and suppression with project 1640 at Palomar

Gautam Vasisht; Eric Cady; Chengxing Zhai; Thomas Lockhart; Ben Oppenheimer

doi:10.1117/12.2056591

22 August 2014 Realtime speckle sensing and suppression with project 1640 at Palomar

Gautam Vasisht, Eric Cady, Chengxing Zhai, Thomas Lockhart, Ben Oppenheimer

Proceedings Volume 9148, Adaptive Optics Systems IV; 914822 (2014) https://doi.org/10.1117/12.2056591
Event: SPIE Astronomical Telescopes + Instrumentation, 2014, Montréal, Quebec, Canada

Abstract

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.

Citation Download Citation

Gautam Vasisht, Eric Cady, Chengxing Zhai, Thomas Lockhart, and Ben Oppenheimer "Realtime speckle sensing and suppression with project 1640 at Palomar", Proc. SPIE 9148, Adaptive Optics Systems IV, 914822 (22 August 2014); https://doi.org/10.1117/12.2056591

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available