The Adaptive Optics System for the Gemini Infrared Multi-Object Spectrograph: Performance Modeling

The Gemini Infrared Multi-Object Spectrograph (GIRMOS) will be a near-infrared, multi-object, medium spectral resolution, integral field spectrograph (IFS) for Gemini North Telescope, designed to operate behind the future Gemini North Adaptive Optics system (GNAO). In addition to a first ground layer Adaptive Optics (AO) correction in closed loop carried out by GNAO, each of the four GIRMOS IFSs will independently perform additional multi-object AO correction in open loop, resulting in an improved image quality that is critical to achieve top level science requirements. We present the baseline parameters and simulated performance of GIRMOS obtained by modeling both the GNAO and GIRMOS AO systems. The image quality requirement for GIRMOS is that 57% of the energy of an unresolved point-spread function ensquared within a 0.1 x 0.1 arcsecond at 2.0 {\mu} m. It was established that GIRMOS will be an order 16 x 16 adaptive optics (AO) system after examining the tradeoffs between performance, risks and costs. The ensquared energy requirement will be met in median atmospheric conditions at Maunakea at 30{\deg} from zenith.Comment: 13 pages, 10 figures, Publications of the Astronomical Society of the Pacifi

Focal plane wavefront sensing on SUBARU/SCExAO

Focal plane wavefront sensing is an elegant solution for wavefront sensing since near-focal images of any source taken by a detector show distortions in the presence of aberrations. Non-Common Path Aberrations and the Low Wind Effect both have the ability to limit the achievable contrast of the finest coronagraphs coupled with the best extreme adaptive optics systems. To correct for these aberrations, the Subaru Coronagraphic Extreme Adaptive Optics instrument hosts many focal plane wavefront sensors using detectors as close to the science detector as possible. We present seven of them and compare their implementation and efficiency on SCExAO. This work will be critical for wavefront sensing on next generation of extremely large telescopes that might present similar limitations

Calibrating the Non-Common Path Aberrations on the MOAO system RAVEN and

Contemporary AO systems, such as the Multi-Object Adaptive Optics system (MOAO) RAVEN currently associated with the Subaru Telescope, can suer from signicant Non-Common Path Aberrations (NCPA). These errors ultimately aect image quality and arise from optical path dierences between the wavefront sensor (WFS) path and the science path. A typical correction of NCPA involves estimating the aberration phase and correcting the system with an oset on the deformable mirror (DM). We summarize two methods used to correct for NCPA on an experimental bench. We also successfully calibrate the NCPA on RAVEN using one of these methods. Finally, we report on some rst science results with RAVEN, obtained after NCPA correction.

Calibrating the Non-Common Path Aberrations on the MOAO system RAVEN and

Contemporary AO systems, such as the Multi-Object Adaptive Optics system (MOAO) RAVEN currently associated with the Subaru Telescope, can suer from signicant Non-Common Path Aberrations (NCPA). These errors ultimately aect image quality and arise from optical path dierences between the wavefront sensor (WFS) path and the science path. A typical correction of NCPA involves estimating the aberration phase and correcting the system with an oset on the deformable mirror (DM). We summarize two methods used to correct for NCPA on an experimental bench. We also successfully calibrate the NCPA on RAVEN using one of these methods. Finally, we report on some rst science results with RAVEN, obtained after NCPA correction.

Non-common path aberration corrections for current and future AO systems

ABSTRACT We explore two methods of quantifying and correcting non-common path aberrations (NCPA) both in simulation and on an experimental bench. The first method, called Focal Plane Sharpening (FPS), utilizes an optimization algorithm to maximize the peak intensity of the PSF by varying actuator patterns on a deformable mirror (DM). The second method employs the technique of Phase Diversity (PD) to estimate NCPA by use of PSF images in and out of the focal plane. The experimental tests use a 52 actuator ALPAO DM and 1000 actuator MEMS DM to provide an offset for NCPA correction. Each method shows to be successful in simulation, however FPS is the only method used successfully on an experimental bench; although work is on-going to successfully demonstrate PD. Our aim is to use one or both methods to determine the best approach to NCPA calibration on the MOAO system RAVEN, and extend this calibration method to future systems such as TMT's NFIRAOS

On-sky results of Raven, a MOAO science demonstrator at Subaru Telescope

Raven is a Multi-Object Adaptive Optics science demonstrator which has been used on-sky at Subaru telescope from May 2014 to July 2015. Raven has been developed at the University of Victoria AO Lab, in partnership with NRC, NAOJ and Tohoku University. Raven includes three open loop WFSs, a central laser guide star WFS, and two science pick-off arms feeding light to the Subaru IRCS spectrograph. Raven supports different AO modes: SCAO, open-loop GLAO and MOAO. This paper gives an overview of the instrument design, compares the on-sky performance of the different AO modes and presents some of the science results achieved with MOAO