Here is an example of a typical FITS header from an APT image. It is designed to be fairly self-explanatory. The header keywords have been selected for compatibility with the IRAF packages ``ccdred'' from NOAO and ``gasp'' from STSDAS. The only problem is the non-standard use of ``BITPIX = -16''. Standard IRAF procedures can be used to automatically add the Julian Date, sidereal time, and airmass, to the header based on the information written by the APT.
SIMPLE = T BITPIX = -16 / unsigned 16-bit integers NAXIS = 2 / 2-dimensional image NAXIS1 = 100 / x dimension NAXIS2 = 100 / y dimension BAXIS1 = 1 / x binning factor BAXIS2 = 1 / y binning factor DATASEC = '[1:100,1:100]' / image section containing data VERSION = 'MCCD version 2.1' / version of the acquisition software used IMAGETYP= 'dark ' / type of image SUBSET = 'V ' / filter used OBJECT = 'ngc6302 ' / the name of the object observed OBSERVER= 'Michael Ashley ' / the name of the observer RA = 18.12320000 / right ascension [hours] DEC = -33.44300000 / declination [degrees] CRVAL1 = 210.56466666 / right ascension of reference position [degrees] CRVAL2 = -33.44300000 / declination of reference position [degrees] EQUINOX = 2000.000 / equinox of coordinates EPOCH = 1995.400049 / epoch of observations CRPIX1 = 50 / x coordinate of reference position [pixels] CRPIX2 = 50 / y coordinate of reference position [pixels] XPIXELSZ= 22.5 / x pixel size [microns] YPIXELSZ= 22.5 / y pixel size [microns] PLATESCL= 419.111 / plate scale [arcsecs/mm] XCOEFF1 = / 1st X coeff [arcsecs/mm] XCOEFF2 = / 2nd YCOEFF1 = / 1st Y coeff [arcsecs/mm] YCOEFF2 = / 2nd DATE-OBS= '15/05/1995' / local date of observation [DD/MM/YYYY] TIME-BEG= '13:11:45.665' / local time of exposure [HH:MM:SS.SSS] TIMEZONE= 10 / local time - UT [hours] EXPTIME = 120.000 / exposure time [seconds] DARKTIME= 120.000 / total time since erased [seconds] CAMGAIN = 1 / preamp gain [0 = low; 1 = high] CAMSHIFT= 0 / number of bits shifted right CAMSPEED= 0 / readout speed [0 = low; 1 = high] CCDREAD = 4.7 / readout noise [electrons] CCDGAIN = 10.2 / CCD gain [electrons/adu] FOCUS = 120 / focus position [steps] OBSERVAT= 'SSO ' / observatory LAT_OBS = -31.27336 / observatory latitude [degrees] LONG_OBS= 210.93881 / observatory longitude [degrees] ALT_OBS = 1149 / observatory altitude [meters] TIMEZONE= -10 / observatory timezone [hours] TELESCOP= 'AUTOMATED PATROL TELESCOPE' INSTRUME= 'WRIGHT CAMERA; EEV CCD; 770x1152' INSTITUT= 'UNIVERSITY OF NEW SOUTH WALES' EMAIL = 'mcba@newt.phys.unsw.edu.au' / Michael Ashley's e-mail address WWW = 'http://www.phys.unsw.edu.au/~mcba/apt.html' / WWW info on APT