Q: What is the current status of the Optical Field Angle Distortion (OFAD) calibration?
A: The Space Telescope Astrometry Team (STAT) has calibrated the optical distortions in FGS 3 for both before and after the Servicing Mission (during which COSTAR was installed). The solutions are different since the secondary mirror was moved after the installation of COSTAR and this affected the OFAD. The Team is currently solving for a time-dependent OFAD solution; more information will be posted as it becomes available.