  We report on the marginal detection of cosmic shear on sub-arcmin scales with
archive data from the STIS camera on board HST. For the measurement 121 galaxy
fields with a field of view of 51'' x 51'' are used to obtain an rms cosmic
shear of ~ 4% with 1.5sigma significance. This value is consistent with
groundbased results obtained by other groups on larger scales, and with
theoretical predictions for a standard LambdaCDM cosmology. To show the
suitability of STIS for weak shear measurements we carefully investigated the
stability of the PSF. We demonstrate that small temporal changes do not affect
the cosmic shear measurement by more than ~ 10%. We also discuss the influence
of various weighting and selection schemes for the galaxy ellipticities.
