bschlesinger@nssdca.gsfc.nasa.gov (Barry Schlesinger) (11/08/90)
Fundamental FITS information can be obtained primarily from three papers: Wells, Greisen, and Harten, 1981, "FITS: a flexible image transport system", Astronomy and Astrophysics Supplements, v. 44, p. 363. Grosbol, et al., 1988, "Generalized extensions and blocking factors for FITS", Astron. Astrophys. Suppl., 88, 359. Harten, et al., 1988, "The FITS tables extension", Astron. Astrophys. Suppl., 88, 365. These titles show that FITS is capable of transforming a far wider range of information than simply digital images. An additional paper immediately following the first one cited above discusses "groups" format. In practice, this format is used only to transfer and store radio interferometry results. It is not widely used or understood elsewhere. In original FITS, as discussed in the first paper, the data matrix could contain only integers. By international agreement, it now may contain IEEE-754 single and double precision floating point. A data matrix consisting of floating point numbers is signalled by negative values of the BITPIX keyword (-32 for single and -64 for double precision). The FITS Handbook is not yet available; the first sections are expected to be available later this year. We have not yet collected contributed software. Probably, this office will have available information on availability of software that the originators are willing to make available before software is available directly from this office. Barry Schlesinger NSDSSO FITS Support Office
bschlesinger@nssdca.gsfc.nasa.gov (Barry Schlesinger) (11/09/90)
This information is posted in response to requests for where general FITS information can be found. The best references are the following three papers: Wells, Greisen, and Harten, 1981, "FITS: a flexible image transport system", Astronomy and Astrophysics Supplements, v. 44, p. 363. Grosbo\"l et al., 1988, "Generalized extensions and blocking factors for FITS", Astron. Astrophys. Suppl., 88,359. Harten et al., 1988, "The FITS tables extension", Astron. Astrophys. Suppl., 88,365. The titles of these papers show that FITS is not exclusively for the transport of digital images but can transport a wider variety of structures. An additional paper, immediately following the 1981 paper cited above discussed "groups" format. In practice, this format is used only to transfer and store radio interferometry results. It is not widely used or understood elsewhere. Originally, as discussed in the first FITS paper, the data matrix could contain only integers. By international agreement, it now may contain IEEE-754 single and double precision floating point numbers. If a data matrix is composed of floating point numbers, then the BITPIX keyword in the preceding header has a negatrive value (-32 for single and -64 for double precision). The FITS Handbook is not yet available; the first sections, covering the Introduction, FITS history, and FITS fundamentals are expected to be available later this year. We have not yet collected contributed software. Probably, this office will have information on software that the originators are willing to make publicly available before the office itself has software to distribute. Barry Schlesinger NSDSSO FITS Support Office