8 Summary

We have developed a flexible method for associating celestial coordinates with a FITS image and implemented it for all projections likely to be of use in astronomy. It should be a relatively simple matter to add new projections should the need ever arise.

The FITS-header keywords defined in this paper are summarized in Table 12 with the 3-letter projection codes listed in Table 13. The column labeled $\theta _0$ gives the native latitude of the reference point in degrees ( $\phi_0 = 0$ always) and the parameters associated with each projection are listed in the nomenclature of Sect. 5.

Acknowledgements

The authors would particularly like to thank Patrick Wallace (U.K. Starlink) for his helpful comments which included the text for some of the paragraphs of Sect. 3.1 and the suggestion of the zenithal polynomial projection. Also, Steve Allen (UCO/Lick Observatory) who provided valuable feedback and suggestions over the long period of this work's development. We are grateful for the assistance provided by Bob Hanisch (Space Telescope Science Institute) in bringing the manuscript to its final form. We also thank William Pence, Arnold Rots, and Lorella Angelini (NASA Goddard Space Flight Center) for contributing the text of Sect. 4.

The authors thank the following for comments and suggestions: Rick Balsano, David Berry, Emmanuel Bertin, Jeff Bloch, Peter Bunclark, Julian Daniels, Lindsey Davis, Rick Ebert, Douglas Finkbeiner, Immanuel Freedman, Brian Glendenning, Bill Gray, Dave Green, Mike Kesteven, Doug Mink, Jonathan McDowell, François Ochsenbein, Fred Patt, Tim Pearson, William Thompson, Doug Tody, Stephen Walton, and Don Wells.

Many others contributed indirectly via requests for clarification of particular points leading potentially to improvements in the wording or formalism.

Mark Calabretta would also like to thank the following for feedback on WCSLIB: Klaus Banse, David Barnes, David Berry, Wim Brouw, Lindsey Davis, Rick Ebert, Ken Ebisawa, Brian Glendenning, Neil Killeen, Thomas A. McGlynn, Doug Mink, Clive Page, Ray Plante, Keith A. Scollick, and Peter Teuben.

Coastline data for Fig. 36 are from the "CIA World DataBank II'' map database, which is in the public domain. Dave Pape's plain-text version was obtained from http://www.evl.uic.edu/pape/data/WDB/ and this site also provides references to the original, highly compressed binary encodings.

The Australia Telescope is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO.

The National Radio Astronomy Observatory is a facility of the (U.S.) National Science Foundation operated under cooperative agreement by Associated Universities, Inc.