FAR-ULTRAVIOLET IMAGING OF THE GLOBULAR-CLUSTER NGC-6681 WITH WFPC2

We have imaged the globular cluster NGC 6681 in the far-UV and visible with WFPC2 on the HST. Our far-UV images show a sparsely populated an d fully resolved central region, and we detect 122 stars. The far-UV t o visible color-magnitude diagram shows a well-defined horizontal bran ch with no evidence for hot, more evolved descendants. We find one hot horizontal-branch star significantly below the model zero-age horizon tal branch, but the rest are consistent with evolutionary models withi n uncertainties in calibration, distance, and reddening. The center of the cluster harbors two luminous blue stragglers. Our far-UV images g raphically confirm that there is no steep density gradient at small ra dii among the horizontal-branch stars of this post-core-collapse clust er and show no evidence for significant color gradients.