Estimation of the GMT inter-segment piston error from deformable mirror commands

Michael Hart; Runa Briguglio; Enrico Pinna; Alfio Puglisi; Fernando Quiros; Marco Xompero

doi:10.1117/12.902653

16 September 2011 Estimation of the GMT inter-segment piston error from deformable mirror commands

Michael Hart, Runa Briguglio, Enrico Pinna, Alfio Puglisi, Fernando Quiros, Marco Xompero

Proceedings Volume 8149, Astronomical Adaptive Optics Systems and Applications IV; 81490B (2011) https://doi.org/10.1117/12.902653
Event: SPIE Optical Engineering + Applications, 2011, San Diego, California, United States

Abstract

The Giant Magellan Telescope (GMT) will place seven primary mirror segments of 8.4 m diameter on a common mount to form a single co-phased aperture of 25 m. ¹High order adaptive optics (AO) using an adaptive secondary mirror that is segmented in the same way as the primary will correct the telescope's imaging to the diffraction limit in the near infrared. ²Critical to the performance of the telescope will be real-time correction of atmospherically-induced optical path differences between the primary mirror segments. Measuring these errors is challenging because of the large gaps between the segments, where the aberrated wavefront is not explicitly measured by the AO sensors, which are approximately 30 cm even at their narrowest points. In this paper we show that it will be feasible to estimate the path differences between the segments from the commands sent to the adaptive secondary mirror while the AO is running in closed loop. These commands will be an approximate representation of the open-loop atmospheric wavefronts. We have investigated the value of the approach with real-time closed-loop deformable mirror command data from the first-light AO system now running on the Large Binocular Telescope (LBT). ^3,4The data are of very high quality and realistically capture the spatio-temporal behavior of the wavefront. We use data from two nights to show that the GMT segment pathlength errors may be recovered to <25 nm accuracy with a simple linear estimator. Additional simulations show similar performance, which, with high-order AO, is quite adequate to maintain high Strehl ratio at near infrared wavelengths.

Citation Download Citation

Michael Hart, Runa Briguglio, Enrico Pinna, Alfio Puglisi, Fernando Quiros, and Marco Xompero "Estimation of the GMT inter-segment piston error from deformable mirror commands", Proc. SPIE 8149, Astronomical Adaptive Optics Systems and Applications IV, 81490B (16 September 2011); https://doi.org/10.1117/12.902653

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

Members: $17.00

Non-members: $21.00 ADD TO CART

PROCEEDINGS
8 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY

GET CITATION

RIGHTS & PERMISSIONS

Get copyright permission Get copyright permission on Copyright Marketplace

KEYWORDS

Wavefronts

Adaptive optics

Mirrors

Error analysis

Telescopes

Image segmentation

Atmospheric optics

Show All Keywords

Keywords/Phrases

Search In:

Publication Years