Yes. For most scientific HST observations there exists a preview. Depending on the instrument there is an image or spectrum preview provided by courtesy of the CADC. Previews of FORS1 observations are being prepared. Previews can be inspected using Java Applets or by simply downloading the data. Previews are public, i.e., no registration is necessary to access them.

Note: Preview images are reduced in size as well as in dynamic range. In case of spectra the data are binned. Therefore, some features of images and spectra will only show up in the calibrated, full fledged data set.