... HST Overview . ... Part 1 of Volume 1 leads observers through the following three-step process, applicable to HST data files from any instrument: . Chapter 1 on Getting HST Data demonstrates how to search the HST Archive for observations of interest and how to retrieve data. ... Chapter 2 on HST File Formats describes the FITS and GEIS formats used for transferring and reducing HST data. ... Five Appendixes to this handbook, provide some additional general information that you might find useful: . ...