On-sky PSF reconstruction with APETy

Abstract

PSF reconstruction (PSF-R) for AO systems was pioneered by J.P. Veran in 1997 [1] and was successfully demonstrated at CFHT/PUEO. A recent example was presented in the case for the Keck telescope in 2012 [2]. Nevertheless, it has been a constant struggle since to implement these technique as observatory standard. APETy (A PSF Estimation Tool for Yorick) has been developed since 2009 and applied for PSF reconstruction for the Near Infrared Coronograph Imager (NICI) at the Gemini South Observatory based on a 85 element curvature AO system. Using on-sky wavefront sensor data, we estimate the seeing (r0) from deformable mirror commands and reconstruct diffraction limited images (52 mas resulution) with an accuracy of approximately 90% when compared to the science images. APETy is publically available via GitHub (https://github.com/dgratadour/APETy) and can be adapted to other systems. APETy development includes the PSF-R variation proposed by Gendron [3] which proved to be almost 4 times faster than the original approach.