\begin{theindex} \item $N_{\rm bits}$, \hyperpage{10, 11}, \hyperpage{15} \indexspace \item angular units, \hyperpage{8}, \hyperpage{28} \item ANSI, \hyperpage{3}, \hyperpage{38} \item ANSI, IEEE, \hyperpage{14}, \hyperpage{23} \item array descriptor, \hyperpage{20--23}, \hyperpage{25, 26} \item array size, \hyperpage{10, 11}, \hyperpage{15} \item array value, \hyperpage{3, 4}, \hyperpage{13}, \hyperpage{18} \item array, multi-dimensional, \hyperpage{5}, \hyperpage{22}, \hyperpage{27, 28}, \hyperpage{41} \item array, variable-length, \hyperpage{1}, \hyperpage{22}, \hyperpage{25, 26}, \hyperpage{41} \item ASCII character, \hyperpage{3}, \hyperpage{14}, \hyperpage{17--19}, \hyperpage{38} \item ASCII table, \hyperpage{17} \item ASCII text, \hyperpage{3, 4}, \hyperpage{6}, \hyperpage{12}, \hyperpage{19}, \hyperpage{23}, \hyperpage{38} \item ASCII, ANSI, \hyperpage{44} \item AUTHOR, \hyperpage{12} \indexspace \item binary table, \hyperpage{4}, \hyperpage{14}, \hyperpage{19}, \hyperpage{37} \item BITPIX, \hyperpage{10, 11}, \hyperpage{13--17}, \hyperpage{20} \item BLANK, \hyperpage{13, 14} \item blocking, \hyperpage{5} \item BSCALE, \hyperpage{13, 14} \item BUNIT, \hyperpage{13} \item byte order, \hyperpage{5}, \hyperpage{14}, \hyperpage{23} \item BZERO, \hyperpage{13, 14} \indexspace \item case sensitivity, \hyperpage{6}, \hyperpage{8}, \hyperpage{18}, \hyperpage{21} \item character string, \hyperpage{3}, \hyperpage{6}, \hyperpage{19}, \hyperpage{22, 23} \item COMMENT, \hyperpage{6}, \hyperpage{12} \item complex data, \hyperpage{7}, \hyperpage{21}, \hyperpage{23, 24} \item conforming extension, \hyperpage{3--5} \item coordinate systems, \hyperpage{26} \indexspace \item DATAMAX, \hyperpage{13} \item DATAMIN, \hyperpage{13} \item DATE, \hyperpage{11} \item DATE-OBS, \hyperpage{12} \item DATExxxx, \hyperpage{12} \item deprecate, \hyperpage{3, 4}, \hyperpage{6}, \hyperpage{9}, \hyperpage{12}, \hyperpage{14}, \hyperpage{19}, \hyperpage{27, 28}, \hyperpage{31}, \hyperpage{35} \indexspace \item END, \hyperpage{4}, \hyperpage{10}, \hyperpage{15, 16}, \hyperpage{18}, \hyperpage{20}, \hyperpage{25} \item EPOCH, \hyperpage{31} \item EQUINOX, \hyperpage{31} \item EXTEND, \hyperpage{11} \item extension, \hyperpage{3--5}, \hyperpage{13, 14}, \hyperpage{41}, \hyperpage{43} \item extension registration, \hyperpage{5}, \hyperpage{10} \item extension type name, \hyperpage{3}, \hyperpage{5}, \hyperpage{10}, \hyperpage{13} \item extension, conforming, \hyperpage{3--5} \item extension, standard, \hyperpage{4, 5} \item EXTLEVEL, \hyperpage{14} \item EXTNAME, \hyperpage{13} \item EXTVER, \hyperpage{13} \indexspace \item field, empty, \hyperpage{20}, \hyperpage{23} \item file size, \hyperpage{4} \item fill, \hyperpage{4--6}, \hyperpage{10}, \hyperpage{16}, \hyperpage{18, 19}, \hyperpage{22}, \hyperpage{25} \item FITS structure, \hyperpage{3, 4}, \hyperpage{6}, \hyperpage{11} \item floating-point, \hyperpage{7}, \hyperpage{23}, \hyperpage{38} \item floating-point {\em FITS\/} agreement, \hyperpage{44} \item floating-point, complex, \hyperpage{7}, \hyperpage{23} \item format, data, \hyperpage{14} \item format, fixed, \hyperpage{6} \item format, free, \hyperpage{6, 7}, \hyperpage{34} \item format, keywords, \hyperpage{6} \item Fortran, \hyperpage{5}, \hyperpage{17--19}, \hyperpage{21, 22}, \hyperpage{44} \indexspace \item GCOUNT, \hyperpage{11}, \hyperpage{15--17}, \hyperpage{20} \item group parameter value, \hyperpage{3}, \hyperpage{15, 16} \item GROUPS, \hyperpage{15} \indexspace \item HDU, \hyperpage{3}, \hyperpage{10} \item HDU, extension, \hyperpage{3, 4} \item HDU, primary, \hyperpage{3--5} \item heap, \hyperpage{3}, \hyperpage{11}, \hyperpage{20--23}, \hyperpage{25, 26} \item HISTORY, \hyperpage{6}, \hyperpage{12} \item hyphen, \hyperpage{6}, \hyperpage{18}, \hyperpage{21}, \hyperpage{28}, \hyperpage{31} \indexspace \item IAU, \hyperpage{1}, \hyperpage{3}, \hyperpage{44} \item IAU Style Manual, \hyperpage{8}, \hyperpage{44} \item IAUFWG, \hyperpage{1}, \hyperpage{3}, \hyperpage{5}, \hyperpage{10}, \hyperpage{26}, \hyperpage{41} \item IEEE floating-point, \hyperpage{14} \item IEEE special values, \hyperpage{3}, \hyperpage{13, 14}, \hyperpage{38} \item image extension, \hyperpage{16} \item INSTRUME, \hyperpage{12} \item integer, 16-bit, \hyperpage{14}, \hyperpage{23} \item integer, 32-bit, \hyperpage{14}, \hyperpage{23} \item integer, 64-bit, \hyperpage{14}, \hyperpage{23} \item integer, 8-bit, \hyperpage{14}, \hyperpage{23} \item integer, complex, \hyperpage{7} \item integer, unsigned, \hyperpage{13, 14}, \hyperpage{21}, \hyperpage{23} \indexspace \item keyword record, \hyperpage{4}, \hyperpage{6} \item keyword, commentary, \hyperpage{6}, \hyperpage{12} \item keyword, indexed, \hyperpage{3}, \hyperpage{6}, \hyperpage{10} \item keyword, mandatory, \hyperpage{6}, \hyperpage{10}, \hyperpage{15--17}, \hyperpage{20}, \hyperpage{37} \item keyword, new, \hyperpage{14} \item keyword, order, \hyperpage{10}, \hyperpage{15}, \hyperpage{17} \item keyword, required, \hyperpage{4}, \hyperpage{10}, \hyperpage{15, 16}, \hyperpage{20} \item keyword, reserved, \hyperpage{4}, \hyperpage{11}, \hyperpage{15, 16}, \hyperpage{18}, \hyperpage{20}, \hyperpage{28, 29}, \hyperpage{37} \item keyword, valid characters, \hyperpage{6} \indexspace \item logical value, \hyperpage{7}, \hyperpage{23, 24} \indexspace \item magnetic tape, \hyperpage{5} \indexspace \item NaN, IEEE, \hyperpage{14}, \hyperpage{23}, \hyperpage{38, 39} \item NAXIS, \hyperpage{4, 5}, \hyperpage{10, 11}, \hyperpage{15--17}, \hyperpage{20} \item NAXIS1, \hyperpage{15}, \hyperpage{17, 18}, \hyperpage{20}, \hyperpage{22}, \hyperpage{25} \item NAXIS2, \hyperpage{17, 18}, \hyperpage{20}, \hyperpage{22}, \hyperpage{25} \item NAXISn, \hyperpage{4, 5}, \hyperpage{10, 11}, \hyperpage{15, 16} \item NULL, ASCII, \hyperpage{3}, \hyperpage{23} \indexspace \item OBJECT, \hyperpage{12} \item OBSERVER, \hyperpage{12} \item order, byte, \hyperpage{5}, \hyperpage{14}, \hyperpage{23} \item order, extensions, \hyperpage{5} \item order, keyword, \hyperpage{6}, \hyperpage{10}, \hyperpage{15}, \hyperpage{17} \item order, {\em FITS\/} structures, \hyperpage{4} \item ORIGIN, \hyperpage{11} \indexspace \item PCOUNT, \hyperpage{11}, \hyperpage{15--17}, \hyperpage{20}, \hyperpage{25} \item physical value, \hyperpage{3, 4}, \hyperpage{13}, \hyperpage{15, 16}, \hyperpage{18}, \hyperpage{21} \item primary data array, \hyperpage{3, 4}, \hyperpage{15, 16} \item primary header, \hyperpage{3, 4}, \hyperpage{10}, \hyperpage{15} \item PSCALn, \hyperpage{15, 16} \item PTYPEn, \hyperpage{15, 16} \item PZEROn, \hyperpage{15, 16} \indexspace \item random groups, \hyperpage{3}, \hyperpage{13--15} \item random groups array, \hyperpage{15} \item REFERENC, \hyperpage{12} \item repeat count, \hyperpage{4}, \hyperpage{20}, \hyperpage{23} \indexspace \item scaling, data, \hyperpage{15, 16}, \hyperpage{18}, \hyperpage{21} \item sign bit, \hyperpage{14} \item sign character, \hyperpage{7}, \hyperpage{19} \item SIMPLE, \hyperpage{5}, \hyperpage{10}, \hyperpage{15} \item slash, \hyperpage{6}, \hyperpage{8} \item special records, \hyperpage{3--5} \item special values, IEEE, \hyperpage{23} \item standard extension, \hyperpage{4, 5} \indexspace \item TABLE, \hyperpage{17} \item TBCOLn, \hyperpage{17} \item TDIMn, \hyperpage{22} \item TDISPn, \hyperpage{18}, \hyperpage{21} \item TELESCOP, \hyperpage{12} \item TFIELDS, \hyperpage{17}, \hyperpage{20} \item TFORMn, \hyperpage{17}, \hyperpage{20}, \hyperpage{23}, \hyperpage{25} \item THEAP, \hyperpage{22}, \hyperpage{25} \item time, \hyperpage{11, 12}, \hyperpage{31}, \hyperpage{35} \item time, universal, \hyperpage{11} \item TNULLn, \hyperpage{18, 19}, \hyperpage{21}, \hyperpage{23} \item TSCALn, \hyperpage{18}, \hyperpage{21}, \hyperpage{25} \item TTYPEn, \hyperpage{18}, \hyperpage{20} \item TUNITn, \hyperpage{18}, \hyperpage{21} \item two's complement, \hyperpage{14}, \hyperpage{23} \item TZEROn, \hyperpage{18}, \hyperpage{21}, \hyperpage{25} \indexspace \item underscore, \hyperpage{6}, \hyperpage{18}, \hyperpage{21} \item units, \hyperpage{4}, \hyperpage{8}, \hyperpage{13}, \hyperpage{18}, \hyperpage{21}, \hyperpage{28}, \hyperpage{32} \indexspace \item value, \hyperpage{6}, \hyperpage{11} \item value, undefined, \hyperpage{6, 7}, \hyperpage{13, 14}, \hyperpage{18, 19}, \hyperpage{21}, \hyperpage{42} \item variable-length array, \hyperpage{1}, \hyperpage{22}, \hyperpage{25, 26}, \hyperpage{41} \indexspace \item WCS, \hyperpage{26} \item WCS, celestial, \hyperpage{30} \item WCS, spectral, \hyperpage{31} \indexspace \item XTENSION, \hyperpage{3}, \hyperpage{5}, \hyperpage{10}, \hyperpage{13}, \hyperpage{16, 17}, \hyperpage{20} \end{theindex}