Optimizing pixfrac in Astrodrizzle: An example from the Hubble Frontier Fields

We present the results of pixfrac tests conducted for the Hubble Frontier Fields and describe the methodology for optimizing this parameter for any given plate scale. These tests are the final step in the drizzling process and they provide the information necessary for reaching the best possible image resolution using the AstroDrizzle task. They are presented as an example for users to follow. Even though most users don’t have an exquisite data set like the HFF program, which consists of a large number of optimally dithered frames, these guidelines are still applicable to single visit programs that make use of sub-sampling dither patterns. We also provide code that cycles through some of the relevant parameter space and provides useful statistical analysis for inspection.