  We present a spectroscopic analysis of HST/STIS and FOS low- and
intermediate-resolution spectroscopy of 55 stars (turn-off stars, horizontal
branch stars and blue stragglers) in four globular clusters (47 Tucanae, M3,
NGC6752, and NGC6397). Stars were analyzed with non-Local Thermodynamic
Equilibrium model atmospheres, and values for their effective temperatures and
gravities and some rotation rates were obtained. Using photometric fluxes, we
also obtained radii, luminosities and spectroscopic masses.
