The age of the Sculptor dwarf spheroidal galaxy from imaging with WFPC2

From images taken with the Hubble Space Telescope's WFPC2, we have obtained photometry of a field in the Sculptor dwarf spheroidal galaxy to 3 mag below the main-sequence turnoff. We determine an age equal to that of the earliest globular clusters for the bulk of the stars in our field of view. We attempt to constrain the star formation history of the Sculptor dwarf by examining the main-sequence luminosity function. The presence of a half-dozen blue straggler candidates blueward of the turnoff points to a possibly complex star formation history. However, the contribution of any intermediate-age population is difficult to measure conclusively, because of the uncertain origin of blue stragglers and the sparseness of the photometric sample.