Estimation and application of the solar adaptive optics corrected long-exposure point spread function

Abstract

Telemetry data from the solar adaptive optics (AO) system at the 0.76m aperture Dunn Solar Telescope (DST) was used to estimate the long-exposure point spread function (PSF) delivered by the AO. The AO-corrected images were deconvolved ex post facto using the PSF estimate in order to improve the quantitative photometry of the images and the reliability of other derived physical quantities. Observations of the bright star Sirius obtained with the solar AO system produced direct measurements of the long-exposure PSF that were compared to the estimated PSFs. The match between estimates and direct measurements of the PSF is excellent, thus validating the implementation of the PSF estimation method for the DST AO system, which deploys a correlating Shack–Hartmann wavefront sensor. The beneficial effect of postprocessing long-exposure solar images with the estimated PSFs is demonstrated for several observing situations, including stable and variable seeing conditions. The advantages and limitations of the application of the PSF estimation method to solar imagery and the quantitative measurements obtained from the observations are discussed in the broader context of solar AO observations.