On-sky demonstration of matched filters for wavefront measurements using ELT-scale elongated laser guide stars
Abstract
The performance of adaptive optics systems is partially dependent on the algorithms used within the real-time control system to compute wavefront slope measurements. We demonstrate the use of a matched filter algorithm for the processing of elongated laser guide star (LGS) Shack-Hartmann images, using the CANARY adaptive optics instrument on the 4.2 m William Herschel Telescope and the European Southern Observatory Wendelstein LGS Unit placed 40 m away. This algorithm has been selected for use with the forthcoming Thirty Meter Telescope, but until now had not been demonstrated on-sky. From the results of a first observing run, we show that the use of matched filtering improves our adaptive optics system performance, with increases in on-sky H-band Strehl measured up to about a factor of 1.1 with respect to a conventional centre of gravity approach. We describe the algorithm used, and the methods that we implemented to enable on-sky demonstration.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- April 2017
- DOI:
- 10.1093/mnras/stx062
- arXiv:
- arXiv:1702.03736
- Bibcode:
- 2017MNRAS.466.5003B
- Keywords:
-
- instrumentation: adaptive optics;
- methods: numerical;
- Astrophysics - Instrumentation and Methods for Astrophysics
- E-Print:
- Accepted for publication in MNRAS