On-sky MOAO performance evaluation of RAVEN

Abstract

This paper presents the AO performance we got on-sky with RAVEN, a Multi-Object Adaptive Optics (MOAO) technical and science demonstrator installed and tested at the Subaru telescope. We report Ensquared-Energy (EE) and Full Width at Half Maximum (FWHM) measured from science images on Subaru's IRCS taken during all of the on-sky observing runs. We show these metrics as function of different AO modes and atmospheric conditions for two asterisms of natural guide stars. The performances of the MOAO and Ground-Layer AO (GLAO) modes are between the classical Single-Conjugate AO (SCAO) and seeing-limited modes. We achieve the EE of 30 % in H-band with the MOAO correction, which is a science requirement for RAVEN. The MOAO provides sightly better performance than the GLAO mode in both asterisms. One of the reasons which cause this small difference between the MOAO and GLAO modes may be the strong GL contribution. Also, the performance of the MOAO modes is affected by the accuracy of the on-sky turbulence profiling by the SLOpe Detection And Ranging (SLODAR) method.

ULTIMATE-Subaru: Wide-field Near-infrared Surveyor with GLAO at Subaru telescope

“…The expected image quality after the GLAO correction at Subaru is FWHM ~ 0.2 arcsec in K-band under a moderate seeing condition of FWHM ~0.4 arcsec over ~20 arcmin FoV. We confirmed that the results of the simulation in H band is consistent with the on-sky results by RAVEN 11 at the Subaru telescope in GLAO mode 12 , demonstrating the feasibility to achieve the performance of the GLAO as expected. To predict the sensitivity of the ULTIMATE-Subaru NIR instruments, we conducted the performance modeling of the instruments using the PSF obtained from the GLAO simulation.…”

Adaptive Optics for Extremely Large Telescopes

“…The ¯rst MOAO system installed on a 8 m class telescope was the RAVEN (Andersen et al, 2012;Lardière et al, 2014;Davidge et al, 2015;Ono et al, 2016;Lamb et al, 2017) demonstrator, which was in operation at the Subaru telescope between 2014 and 2015. Developed as a path¯nder for the 30 m TMT, results obtained with this instrument are encouraging, with better performance than GLAO (Fig.…”

Optimizing the accuracy and efficiency of optical turbulence profiling using adaptive optics telemetry for extremely large telescopes

“…Investigations indicate that the outer scale resides between 1-100 m (Ziad et al 2004). However, using the SLODAR technique the existing class of telescopes do not have the spatial scale to construct an un-biased L 0 profile (Ono et al 2016). It was shown by Guesalaga et al (2017) that there is no significant difference in SLODAR data analysis when the outer scale is over roughly 3 times the diameter of the telescope pupil.…”

“…By averaging covariance matrix baselines the optical turbulence profile can be studied as a covariance map. Previous studies have shown that a covariance map region of interest (ROI) can be used to perform SLODAR data analysis (Butterley, Wilson & Sarazin 2006;Cortés et al 2012;Guesalaga et al 2014;Guesalaga et al 2017;Ono et al 2016). However, an investigation into the optimal size of the covariance map ROI has not been published.…”