NGS WFSs module for MAORY at E-ELT

Journal
Date Issued
2015
Author(s)
•
•
Antichi, J.
•
Bonanno, A.
•
•
Giordano, C.
•
Spanò, P.
Abstract
We report on the natural guide star (NGS) wavefront sensors (WFS) module for MAORY, the multi-cojugate adaptive optics (MCAO) system for the ESO E-ELT. Three low-order, near-infrared (H-band), Shack-Hartmann sensors provide fast acquisition of the first 5 modes (tip, tilt, focus, astigmatism) on 3 natural guide stars over a 160 arcsec field of view. Three moderate-order (20x20), visible (600-800 nm), pyramid WFSs provide the slow Truth sensing to correct LGS wavefront estimates of low-order modes. These sensors are mounted onto three R-theta stages to patrol the field of view. The module is also equipped with a retractable, on-axis, high-order (80x80), visible, pyramid WFS for the single-conjugate AO (SCAO) mode of MAORY and MICADO. The visible WFSs share the same 80x80 pyramid WFS design. This choice enables also a MCAO NGS capability. Simulations show that Strehl ratios (SR) over 40% are reached with MCAO and three, 2x2 sub-apertures, NIR low-order WFSs working with H-mag=20 reference stars. In SCAO mode, 90% SR for a 8mag stars with a contrast down to 10-5, and 45% SR for a 16mag star, are achieved.
Volume
86
Start page
446
Uri
Url
Issn Identifier
0037-8720
Ads BibCode
2015MmSAI..86..446E
Rights
open.access
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