\begin{theindex}

  \item $N_{\rm bits}$, 30, 32, 43

  \indexspace

  \item angular units, 23
  \item ANSI, 7
  \item ANSI, IEEE, 40, 65
  \item array descriptor, 65, 71
  \item array size, 30, 31, 43, 44
  \item array value, 7, 10, 35
  \item array, multi-dimensional, 14
  \item array, variable-length, 68, 71
  \item ASCII character, 7, 39, 48, 51, 53, 103
  \item ASCII table, 48, 119
  \item ASCII text, 8, 14, 20, 21, 35, 53, 54, 64, 103
  \item ASCII, ANSI, 120
  \item AUTHOR, 34

  \indexspace

  \item binary table, 11, 41, 56, 99, 119
  \item BITPIX, 29, 30, 32, 36, 37, 40, 41, 43, 46, 48, 57
  \item BLANK, 36, 40
  \item BSCALE, 36, 40
  \item BUNIT, 36
  \item byte order, 39
  \item BZERO, 36, 40

  \indexspace

  \item case sensitivity, 19, 21, 27, 50, 59
  \item character string, 8, 21, 54, 61, 64
  \item complex data, 23, 59, 65, 67
  \item conforming extension, 8, 11, 13, 15, 16
  \item coordinate system, 81

  \indexspace

  \item DATAMAX, 37
  \item DATAMIN, 37
  \item DATE, 32
  \item DATE-OBS, 33
  \item DATExxxx, 34
  \item deprecate, 8, 17, 25, 33, 41, 54, 76, 78, 81, 96

  \indexspace

  \item END, 14, 29, 42, 47, 49, 59, 69
  \item EPOCH, 81
  \item EQUINOX, 81
  \item EXTEND, 33
  \item extension, 8, 9, 13, 15, 37, 39, 109, 117
  \item extension registration, 15, 31
  \item extension type name, 8, 15, 31, 37
  \item extension, conforming, 8, 11, 13, 15, 16
  \item extension, standard, 11, 16
  \item EXTLEVEL, 37
  \item EXTNAME, 37
  \item EXTVER, 37

  \indexspace

  \item field, empty, 57, 63
  \item fill, 14, 19, 44, 51, 53, 63
  \item FITS structure, 8--10, 13, 17, 32
  \item floating-point, 22, 65, 105
  \item floating-point {\em FITS\/} agreement, 119
  \item floating-point, complex, 23, 65
  \item format, data, 39
  \item format, fixed, 21
  \item format, free, 21
  \item format, keywords, 21
  \item Fortran, 14, 49, 51, 53, 61, 63, 120

  \indexspace

  \item GCOUNT, 31, 32, 42--44, 46, 49, 57
  \item group parameter value, 9, 43, 44
  \item GROUPS, 42

  \indexspace

  \item HDU, 9, 29
  \item HDU, extension, 8, 13
  \item HDU, primary, 9, 10, 13, 14, 16
  \item heap, 9, 31, 57, 59--61, 65, 69, 70
  \item hyphen, 20

  \indexspace

  \item IAU, 1, 2, 9, 119
  \item IAU Style Manual, 23, 120
  \item IAUFWG, 1, 4, 9, 15, 16, 31, 109
  \item IEEE floating-point, 40
  \item IEEE NaN, 9
  \item IEEE special values, 10, 37, 40, 105
  \item image extension, 45, 119
  \item INSTRUME, 34
  \item integer, 16-bit, 39, 64
  \item integer, 32-bit, 39, 64, 65
  \item integer, 64-bit, 40, 64, 65
  \item integer, 8-bit, 39, 64
  \item integer, complex, 23

  \indexspace

  \item keyword record, 14, 19
  \item keyword, commentary, 20, 34
  \item keyword, indexed, 10, 20, 29
  \item keyword, mandatory, 48
  \item keyword, new, 38
  \item keyword, order, 28, 30, 41, 48
  \item keyword, required, 10, 28, 30, 41, 45, 56
  \item keyword, reserved, 11, 32, 43
  \item keyword, valid characters, 19

  \indexspace

  \item logical value, 21

  \indexspace

  \item mantissa, 9, 10

  \indexspace

  \item NaN, IEEE, 65
  \item NAXIS, 14, 29, 30, 32, 41, 43, 44, 46, 49, 57
  \item NAXIS1, 42, 49, 51, 57, 61, 63, 69
  \item NAXIS2, 49, 51, 57, 61, 63, 69
  \item NAXISn, 14, 29, 30, 32, 42--44, 46
  \item NULL, ASCII, 7, 64

  \indexspace

  \item OBJECT, 34
  \item OBSERVER, 34
  \item offset, 69
  \item order, byte, 39
  \item order, extensions, 16
  \item order, keyword, 19, 28, 30, 41, 48
  \item order, {\em FITS\/} structures, 13
  \item ORIGIN, 33

  \indexspace

  \item PCOUNT, 31, 32, 42--44, 46, 49, 57, 69
  \item physical value, 7, 10, 35--37, 43, 44, 50, 51, 59
  \item primary data array, 8, 10, 14, 41, 42, 44, 47
  \item primary header, 8, 10, 28, 31, 41
  \item PSCALn, 43, 44
  \item PTYPEn, 43, 44
  \item PZEROn, 43, 44

  \indexspace

  \item random groups, 9, 35, 41, 119
  \item random groups array, 44
  \item REFERENC, 34
  \item repeat count, 11, 57, 63, 64

  \indexspace

  \item scaling, data, 43, 44, 51, 60
  \item sign bit, 39
  \item sign character, 53
  \item significand, 10
  \item SIMPLE, 16, 28, 29, 41
  \item slash, 20
  \item special records, 9, 11, 13, 16
  \item special values, IEEE, 65
  \item standard extension, 11, 16

  \indexspace

  \item TABLE, 48
  \item TBCOLn, 49
  \item TDIMn, 61
  \item TDISPn, 51, 61
  \item TELESCOP, 34
  \item TFIELDS, 49, 57
  \item TFORMn, 49, 57, 63--65, 68
  \item THEAP, 61, 69
  \item time system, 33
  \item TNULLn, 51, 53, 60, 64
  \item TSCALn, 50, 59, 70
  \item TTYPEn, 50, 59
  \item TUNITn, 50, 59
  \item two's complement, 39, 40, 64
  \item TZEROn, 50, 59, 70

  \indexspace

  \item underscore, 20
  \item units, 10, 23, 36, 50, 59
  \item Universal Time, 32

  \indexspace

  \item value, 32
  \item value, undefined, 51, 53, 60
  \item variable-length array, 68, 71

  \indexspace

  \item XTENSION, 8, 16, 31, 37, 45, 48, 56

\end{theindex}