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SECTION 1. INTRODUCTION

One important feature of the FITS format is that its structure, down to the bit

level, is completely specified in documents (such as this standard), many of which have

been published in refereed scientific journals. Given these documents, which are readily

available in hard copy form in libraries around the world as well as in electronic form

on the Internet, future researchers should be able to decode the stream of bytes in any

FITS format data file. In contrast, many other current data formats are only implicitly

defined by the software that read and write the files. If that software is not continually

maintained so that it can be run on future computer systems, then the information

encoded in those data files could be lost.

1.1

Brief History of FITS

The FITS format evolved out of the recognition that a standard format was needed

for transferring astronomical images from one research institution to another. The first

prototype developments of a universal interchange format that would eventually lead to

the definition of the FITS format began in 1976 between Don Wells at KPNO and Ron

Harten at the Netherlands Foundation for Research in Astronomy (NFRA). This need

for an image interchange format was raised at a meeting of the Astronomy section of

the U.S. National Science Foundation in January 1979, which led to the formation of a

task force to work on the problem. Most of the technical details of the first basic FITS

agreement (with files consisting of only a primary header followed by a data array)

were subsequently developed by Don Wells and Eric Greisen (NRAO) in March 1979.

After further refinements, and successful image interchange tests between observatories

that used widely different types of computer systems, the first papers that defined the

FITS format were published in 1981 [2, 3]. The FITS format quickly became the

defacto standard for data interchange within the astronomical community (mostly on

9-track magnetic tape at that time) and was officially endorsed by the IAU in 1982 [1].

Most national and international astronomical projects and organizations subsequently

adopted the FITS format for distribution and archiving of their scientific data products.

Some of the highlights in the developmental history of FITS are shown in Table 1.1

FITS Standard