The documents directory contains a number of subdirectories with various FITS documents. The formats of the documents depend upon the size. Some small documents are available in ASCII text. Larger documents are in PostScript and often in LATEX. The largest documents will also have gzip-compressed PostScript versions as well. The standards subdirectory contains copies of the NOST standard described in section 6.1.2, text of the agreement on physical blocking, and copies of preliminary drafts of the binary table and image extension papers. The overviews subdirectory contains electronic copies of this User's Guide and some FITS history. The proposals subdirectory is for proposals that are ready for consideration by the FITS committees. The drafts subdirectory contains drafts for extensions or conventions that may or may not be submitted to the FITS committees at a future time. The wcs subdirectory contains the current draft proposal for world coordinates conventions (Greisen and Calabretta 1996), draft conventions for world coordinates keywords that would be used in conjunction with this proposal, some earlier documents, and documents discussing map projections.
A directory called os-support is devoted to code for various environments. It contains some software, as well as copies of Usenet postings and mailing list announcements discussing other software. The information extends back over four years.
The data directory contains two subdirectories of FITS files. The samples subdirectory contains a set of FITS data files from different installations covering a number of disciplines, e.g., Hubble Space Telescope, IUE ultraviolet, radio VLBA and single dish measurements, and illustrating FITS conventions, e.g., world coordinates and grouping. The tests subdirectory has under it two subdirectories of test files. One, ftt4b, is a set of FITS files from the early 1980s, which contains a number of images from that era designed for testing FITS files and illustrating possible applications of the format, including the Mandrill to illustrate one way to store RGB. One file also provides a random groups example, which can be used for testing by anyone with a need to read older data in that format. The other subdirectory, pg93, contains test files specially designed for testing the ability of software to handle all standard FITS files, including the primary data array and all standard FITS extensions. In particular, one file contains an array with all the IEEE special values: infinity, NaN, and denormalized numbers. The data are artificial, with values specially selected for the purpose of validating the software's ability to read the data.
The traffic directory contains archives of FITS-related traffic from Usenet newsgroups and mailing list. It includes all postings to sci.astro.fits (the fitsbits mailing list), and FITS-related postings to other newsgroups. It also includes Frequently Asked Questions (FAQ) from selected Usenet newsgroups. FITS-related mailing lists and FITS-related messages from other mailing lists also are archived here.
W. Cotton has developed a family of FITS viewers for Microsoft Windows, Apple Macintosh, and Unix/X-Windows computer systems. These viewers have easy to use graphical controls and are suitable for use as external FITS image viewers for World Wide Web browsers. The programs contain extensive on-line documentation. NRAO distributes these viewers free of charge. Further information on the capabilities of the software and access to it are at http://www.cv.nrao.edu/~bcotton/fitsview.html.