The CHARA array adaptive optics I: common-path optical and mechanical design, and preliminary on-sky results

2014 ◽  
Author(s):  
Xiao Che ◽  
Laszlo Sturmann ◽  
John D. Monnier ◽  
Theo A. ten Brummelaar ◽  
Judit Sturmann ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Mechanical Design ◽  
Common Path ◽  
Chara Array

scholarly journals CHARA array adaptive optics II: non-common-path correction and downstream optics

2014 ◽  
Author(s):  
Theo ten Brummelaar ◽  
Xiao Che ◽  
Harold McAlister ◽  
Michael Ireland ◽  
John Monnier ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Common Path ◽  
Chara Array

OPTICAL AND MECHANICAL DESIGN OF THE CHARA ARRAY ADAPTIVE OPTICS

2013 ◽  
Vol 02 (02) ◽  
pp. 1340007 ◽  
Author(s):  
X. CHE ◽  
L. STURMANN ◽  
J. D. MONNIER ◽  
T. A. TEN BRUMMELAAR ◽  
J. STURMANN ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Near Infrared ◽  
Angular Resolution ◽  
Mechanical Design ◽  
Wavefront Sensor ◽  
High Angular Resolution ◽  
Stellar Systems ◽  
Tilt Correction ◽  
Chara Array ◽  
Adaptive Optics System

The CHARA array is an optical/near infrared interferometer consisting of six 1-meter diameter telescopes with the longest baseline of 331 m. With high angular resolution, the CHARA array provides a unique and powerful way of studying nearby stellar systems. In 2011, the CHARA array was funded by NSF-ATI for an upgrade of adaptive optics systems to all six telescopes to improve the sensitivity by several magnitudes. The initial grant covers Phase I of the adaptive optics system, which includes an on-telescope Wavefront Sensor and fast tip/tilt correction. We are currently seeking funding for Phase II which will add fast deformable mirrors at the telescopes to close the loop. This paper will describe the design of the project, and show simulations of how much improvement the array will gain after the upgrade.

scholarly journals On-sky correction of non-common path aberration with the pyramid wavefront sensor

2020 ◽  
Vol 636 ◽  
pp. A88 ◽  
Author(s):  
S. Esposito ◽  
A. Puglisi ◽  
E. Pinna ◽  
G. Agapito ◽  
F. Quirós-Pacheco ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Critical Issue ◽  
Wavefront Sensor ◽  
Interaction Matrix ◽  
Scientific Instrument ◽  
Wavefront Sensors ◽  
Successful Operation ◽  
Optical Elements ◽  
Common Path ◽  
External Conditions

The paper deals with with the on-sky performance of the pyramid wavefront sensor-based Adaptive Optics (AO) systems. These wavefront sensors are of great importance, being used in all first light AO systems of the ELTs (E-ELT, GMT, and TMT), currently in design phase. In particular, non-common path aberrations (NCPAs) are a critical issue encountered when using an AO system to produce corrected images in an associated astronomical instrument. The AO wavefront sensor (WFS) and the supported scientific instrument typically use a series of different optical elements, thus experiencing different aberrations. The usual way to correct for such NCPAs is to introduce a static offset in the WFS signals. In this way, when the AO loop is closed the sensor offsets are zeroed and the deformable mirror converges to the shape required to null the NCPA. The method assumes that the WFS operation is linear and completely described by some pre-calibrated interaction matrix. This is not the case for some frequently used wavefront sensors like the Pyramid sensor or a quad-cell Shack-Hartmann sensor. Here we present a method to work in closed-loop with a pyramid wavefront sensor, or more generally a non-linear WFS, introducing a wavefront offset that remains stable when AO correction quality changes due to variations in external conditions like star brightness, seeing, and wind speed. The paper details the methods with analytical and numerical considerations. Then we present results of tests executed at the LBT telescope, in daytime and on sky, using the FLAO system and LUCI2 facility instrument. The on-sky results clearly show the successful operation of the method that completely nulls NCPA, recovering diffraction-limited images with about 70% Strehl ratio in H band in variable seeing conditions. The proposed method is suitable for application to the above-mentioned ELT AO systems.

The CHARA array adaptive optics program

2018 ◽  
Author(s):  
Theo A. ten Brummelaar ◽  
Judit Sturmann ◽  
Laszlo Sturmann ◽  
Matthew D. Anderson ◽  
Nils H. Turner ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Chara Array

scholarly journals Adaptive optics for the CHARA array

2012 ◽  
Author(s):  
Theo A. ten Brummelaar ◽  
Laszlo Sturmann ◽  
Judit Sturmann ◽  
Stephen T. Ridgway ◽  
John D. Monnier ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Chara Array

Adaptive optics for the CHARA array II

2010 ◽  
Author(s):  
Stephen Ridgway ◽  
Theo ten Brummelaar ◽  
Judit Sturmann ◽  
Laszlo Sturmann ◽  
Nils Turner ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Chara Array

scholarly journals Common path interferometric wavefront sensor for extreme adaptive optics

2005 ◽  
Vol 13 (9) ◽  
pp. 3491 ◽  
Author(s):  
Gordon D. Love ◽  
Thomas J. D. Oag ◽  
Andrew K. Kirby
Keyword(s):  
Adaptive Optics ◽  
Wavefront Sensor ◽  
Common Path
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