Drizzling Singly-Dithered Hubble Space Telescope Images: A Demonstration

The development of the IRAF/STSDAS package dither and its primary task, drizzle (Fruchter & Hook 1997), now give the HST user powerful tools for combining dithered images; however, these tasks do not provide a simple means for locating and removing cosmic rays, or other blemishes, from dithered images. Here we discuss several additional IRAF scripts that one of us (ASF) has written to simplify the removal of cosmic rays from dithered data. These procedures are particularly useful when only a single image has been taken at a given dither position. We demonstrate these tasks in a cookbook-style by combining a set of singly-dithered WFPC2 images, and give instructions for retrieving these new tasks from the WWW. These tasks are presently in development, and the tasks, and this document, should be considered a “beta” release.