HST Data Handbook for WFPC2

Preface

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Introduction to Reducing HST Data

This data handbook provides an introduction to the process of retrieving and reducing Hubble Space Telescope (HST) data. The reduction procedures, calibrations, and sources of error specific to each active HST instrument (WFPC2, STIS, NICMOS and ACS) are explained in detail in their respective instrument data handbooks. However, we recommend a careful reading of this handbook before proceeding to the instrument data handbooks and before starting to work on your HST data. The present document is an updated version of chapters 1-3 of the HST Data Handbook, v.3.0, and is based on the information available as of December 2001. In particular, it is written under the assumption that the ACS and NICMOS instruments will be fully functional following HST Servicing Mission 3B (SM3B).

Many changes in the HST Data Archive and HST data reduction software have occurred since v. 3.0 of the Hubble Data Handbook. These differences are covered in this document and include, but are not limited to:

1. Expansion of the HST Data Archive into the Multimission Archive at Space Telescope (MAST), which currently includes 14 satellite mission archives as well as ground-based survey data.
2. The ability to retrieve MAST data using the World Wide Web.
3. New capabilities of the StarView program for searching for and retrieving HST and other MAST data.
4. The introduction of PyRAF, a new Python-based alternative to the IRAF cl shell, and
5. A new distinction between waiver FITS format, used to archive data from the older HST instruments such as WFPC and FOS, and the FITS extension format used for the newest instruments (STIS, NICMOS and ACS).

Future changes in this handbook are anticipated as MAST expands to cover additional missions, and as StarView and PyRAF evolve. The reader is advised to consult the STScI web site at http://resources.stsci.edu for the latest information. Moreover, as the present revision comes before SM3B, important revisions to the ACS file structure and data handling may be necessary after the installation of this instrument.

Bahram Mobasher (Chief Editor, HST Data Handbook)

Michael Corbin (Editor, Chapter 1)

Jin-chung Hsu (Editor, Chapters 2 and 3)