WFPC2 Stellar Photometry with HSTPHOT

Abstract

HSTphot, a photometry package designed to handle the undersampled point-spread functions (PSFs) found in WFPC2 images, is introduced and described, as well as some of the considerations that have to be made in order to obtain accurate PSF-fitting stellar photometry with WFPC2 data. Tests of HSTphot's internal reliability are made using multiple observations of the same field, and tests of external reliability are made by comparisons with DoPHOT reductions of the same data.