  Adaptive optics images from the W. M. Keck Observatory have delivered
numerous influential scientific results, including detection of multi-system
asteroids, the supermassive black hole at the center of the Milky Way, and
directly imaged exoplanets. Specifically, the precise and accurate astrometry
these images yield was used to measure the mass of the supermassive black hole
using orbits of the surrounding star cluster. Despite these successes, one of
the major obstacles to improved astrometric measurements is the spatial and
temporal variability of the point-spread function delivered by the instruments.
AIROPA is a software package for the astrometric and photometric analysis of
adaptive optics images using point-spread function fitting together with the
technique of point-spread function reconstruction. In adaptive optics
point-spread function reconstruction, the knowledge of the instrument
performance and of the atmospheric turbulence is used to predict the
long-exposure point-spread function of an observation. In this paper we present
the results of our tests using AIROPA on both simulated and on-sky images of
the Galactic Center. We find that our method is very reliable in accounting for
the static aberrations internal to the instrument, but it does not improve
significantly the accuracy on sky, possibly due to uncalibrated telescope
aberrations.

Instrumentation and Methods for Astrophysics