The HST spherical aberration is responsible for the large point spread function (PSF) already demonstrated in various papers in this volume. Because of the extended PSF, the two HST spectrographs (GHRS and FOS) suffered a significant throughput loss. As a result, the use of the larger apertures was often necessary, with obviously degraded spectral resolution. Our particular emphasis in this work is the restoration of absorption lines blurred by the large line spread function (LSF). An added complication to the problem is the fact that the LSF is very poorly known. The LSFs that are available to us are derived from the PSFs, which in turn are either deduced from observations (e.g., from FOC), or from models (e.g., TinyTIM). The real LSF of course changes with time and focus position, so the LSFs used for our analysis are only approximate.