B.4 IR Summary

Images produced by both WFC3 channels are affected by considerable geometric distortion, dominated by a linear anamorphism introduced by the tilt of the image surface with respect to the chief ray. This is compounded by non-linear terms that produce changes across the field of view in both plate scale and area subtended by the pixels. Distortion solutions derived from data taken during SMOV with UVIS filter F606W and IR filter F160W are presented here. They have been entered into IDCTAB files to support the use of MultiDrizzle to produce distortion-corrected images. (MultiDrizzle has since been replaced by DrizzlePac.) The corresponding pixel area maps, also presented here, have been made available for photometric calibration.