7.3. BINARY TABLE EXTENSION

65

Single Precision Floating-Point  If the value of the TFORMn keyword specifies data

type E, the data in field n shall consist of ANSI/IEEE-754 [21] 32-bit floating-point

numbers, in big endian byte order, as described in Appendix E. All IEEE special values

are recognized. The IEEE NaN is used to represent null values.

Double Precision Floating-Point  If the value of the TFORMn keyword specifies data

type D, the data in field n shall consist of ANSI/IEEE-754 [21] 64-bit double precision

floating-point numbers, in big endian byte order, as described in Appendix E. All IEEE

special values are recognized. The IEEE NaN is used to represent null values.

Single Precision Complex  If the value of the TFORMn keyword specifies data type C,

the data in field n shall consist of a sequence of pairs of 32-bit single precision floating-

point numbers. The first member of each pair shall represent the real part of a complex

number, and the second member shall represent the imaginary part of that complex

number. If either member contains an IEEE NaN, the entire complex value is null.

Double Precision Complex  If the value of the TFORMn keyword specifies data type

M, the data in field n shall consist of a sequence of pairs of 64-bit double precision

floating-point numbers. The first member of each pair shall represent the real part of a

complex number, and the second member of the pair shall represent the imaginary part

of that complex number. If either member contains an IEEE NaN, the entire complex

value is null.

Array Descriptor  The repeat count on the P and Q array descriptor fields must

either have a value of 0 (denoting an empty field of zero bytes) or 1. If the value of

the TFORMn keyword specifies data type 1P, the data in field n shall consist of one pair

of 32-bit integers. If the value of the TFORMn keyword specifies data type 1Q, the data

in field n shall consist of one pair of 64-bit integers. The meaning of these integers is

defined in §7.3.5.

7.3.3.2

Bytes Following Main Table

The main data table may be followed by a supplemental data area called the heap. The

size of the supplemental data area, in bytes, is specified by the value of the PCOUNT

keyword. The use of this data area is described in §7.3.5.

7.3.4

Data Display

The indexed TDISPn keyword may be used to describe the recommended format for

displaying an ASCII text representation of the contents of field n. The permitted display

FITS Standard