4

SECTION 1. INTRODUCTION

Table 1.2.

Version history of the standard.

Version

Date

Status

NOST 100-0.1

1990

December

1st Draft Standard

NOST 100-0.2

1991

June

2nd Revised Draft Standard

NOST 100-0.3

1991

December

3rd Revised Draft Standard

NOST 100-1.0

1993

June

NOST Standard

NOST 100-1.1

1995

September

NOST Standard

NOST 100-2.0

1999

March

NOST Standard

IAUFWG 2.1

2005

April

IAUFWG Standard

IAUFWG 2.1b

2005

December

IAUFWG Standard

IAUFWG 3.0

2008

July

IAUFWG Standard

1.2

Version History of this Document

The fundamental definition of the FITS format was originally contained in a series

of published papers [2, 3, 4, 5]. As FITS became more widely used, the need for a

single document to unambiguously define the requirements of the FITS format became

apparent. In 1990, the NASA Science Office of Standards and Technology (NOST) at the

Goddard Space Flight Center provided funding for a technical panel to develop the first

version of this standard document. As shown in Table 1.2, the NOST panel produced

several draft versions, culminating in the first NOST standard document, NOST 100-1.0,

in 1993. Although this document was developed under a NASA accreditation process, it

was subsequently formally approved by the IAUFWG, which is the international control

authority for the FITS format. The small update to the standard in 1995 (NOST 100-

1.1) added a recommendation on the physical units of header keyword values.

The NOST technical panel was convened a second time to make further updates and

clarifications to the standard, resulting in the NOST 100-2.0 version that was approved

by the IAUFWG in 1999 and published in 2001 [15]. In 2005, the IAUFWG formally

approved the variable-length array convention in binary tables, and a short time later

approved support for the 64-bit integers data type. New versions of the standard were

released to reflect both of these changes (versions IAUFWG 2.1 and IAUFWG 2.1b).

Most recently, the IAUFWG appointed its own technical panel in early 2007 to

consider further modifications and updates to the standard. The changes proposed by

this panel, which were ultimately approved by the IAUFWG after a formal public review

process, are shown in this 3.0 version of the document.

The latest version of the standard, as well as other information about the FITS

format, can be obtained from the FITS Support Office web site at

http://fits.gsfc.nasa.gov.

FITS Standard