The following is a DRAFT list of header words. Key word Example Description 1) Basic FITS SIMPLE= 'T' BITPIX= 16 / Number of bits used for pixel value BSCALE= 1.00000000 /real=bzero=bscale+value BZERO= 32768.00000000 BUNIT= 'ADU' / Data units (ADU or electrons) NAXIS= 2 / Number of coordinate axes NAXIS1= 3550 / Number of pixels in image in x NAXIS2= 3550 / Number of pixles in image in y DATE= '2001-01-28T0' / UT date (yyyy-mm-ddTHH:MM:SS.SS) of file creation 2) Telescope Information DATE-OBS= '2011-01-28T02:03:46.00' / UT date (yyyy-mm-dd)THH:MM:SS.SS of observation UT= ' 2:03:46.00' / UT (start of exposure) ST= ' 6:17:13.000' / Sidereal time (start of exposure) RA= ' 7:57:59.235' / Right ascension (hh:mm:ss.sss) HA= ' -1:40:46.235' / Hour angle (hh:mm:ss.sss) DEC= '-18:13:46.20' / Declination (dd:mm:ss.ss) TELALT- '38:59:03.12' / Telescope Altitutde (dd:mm:ss.ss) TELAZ= '01:22:15.10' / Telescope Azimuth (dd:mm:ss.ss) EQUINOX= 2000.0 / equinox of RA and DEC PA= ' 13:12:15.2' / position angle of detector on sky (dd:mm:ss.s) ROTANGLE= '120:12:15.2' / Rotator angle at start of exposure IAA= ' 12:13:14.5' / Instrument alignment angle AIRMASS= 1.29 / Airmass (start of exposure) ZD= 30.214 / Zenith distance (start of exposure) TELFOCUS= XXXXXX.XX / Telescope focus (not sure of what form this takes) PARANGLE= 12.2 / Parallactic angle (start of exposure) 3) Camera information: OBJECT= 'M31-Field 1' / Object Name from title FPOS1= 3 / position of filter wheel 1 (read from hardware) FPOS2= 10 / position of filter wheel 2 (read from hardware) FILTER1= 'V' / Filter in wheel 1 FILTER2= 'Clear' / Filter in wheel 2 IMAGETYPE 'object'/ Image type (bias, dark, dflat, sflat, object, comp) EXPTIME= 60.000 / Integration time (seconds) 3) WCS for image: RADECSYS= 'FK5 ' CTYPE1 = 'RA---TAN' CTYPE2 = 'DEC--TAN' CRVAL1 = 14.76958 CRVAL2 = 72.17406 CRPIX1 = 1550.0000 CRPIX2 = 1550.0000 CD1_1 = 6.666670E-5 CD1_2 = 0.000000E-6 CD2_1 = 0.000000E-6 CD2_2 = 6.666670E-5 CUNIT1 = 'deg ' CUNIT2 = 'deg ' Note that CRAVL1 and CRVAL2 refer to the ra and dec (in decimal degrees) corresponding to (crpix1,crpix2) in the image. CDi_j is the "rotational matrix", i.e., (RA-CRVAL1) (CD1_1 CD1_2 ) (col-CRPIX1) ( = ( ) x ( ) (DEC-CRVAL2) (CD2_1 CD2_2 ) (row-CRPIX2)) where the units are in degrees per pixel (in the tangent plane). The values above (6.66E-5) are approximately right if the chip is binned 2x2, N is up, and E is to the right (increasing X), I think. If the rotator has a non-zero position angle, than these values have to be adjusted accordingly. We won't know about the signs until we know what amp and the "handiness". 4) Detector key words If only one amplifier is used, then: BIASSEC = '[3551:3582, 1:3550]' / Region of valid overscan for calibration TRIMSEC = '[9:3542, 2:3545]' / Region of valid pixels for extraction CCDSUM = '2 2 ' / On chip summation RDNOISE= 3.6 /e RMS GAIN= 4.2 /e per ADU SCALE = 0.222 /Scale in arcsec per (binned) pixel TEMPCCD = -109.9 /CCD temperature [C] CCDSEC= '[1:3550,1:3550] /Section in full CCD In the event that multiple amplifiers are used, If more than one amplifier is used, Peter's Group II scheme makes good sense: TRIM01, TRIM02, TRIM03, TRIM04 BIAS01, BIAS02, BIAS03, BIAS04 RN01, RN02, RN03, RN04 GAIN01, GAIN02, GAIN03, GAIN4 5) Description of data-taking TELESCOP= 'DCT' / Observatory INSTRUME= 'LMI' / Instrument OBSERVER= 'Collins' / Observer 6) Environment AIR_TEMP= 13.2 /External air temp [C] (UKIRT used "AIR_TEMP" but why not just "AIRTEMP"?) DOMETEMP= 12.1 /Dome air temp [C] MIRRORTEMP= 12.0 /Mirror temp [C] HUMIDITY= 13.0 /Percentage air humidity WIND_SPD= 2.1 /Wind speed [mph] WIND_DIR= 320.1 /Wind direction, azimuth [deg] 7) GWAVES stuff RAP1= ' 7:58:59.235' / Right ascension of Probe 1(hh:mm:ss.sss) DECP1= '-18:15:46.20' / Declination of Probe 1(dd:mm:ss.ss) FILTP1= 'V' / Filter position of Probe 1 RAP2= ' 7:57:59.235' / Right ascension of Probe 2(hh:mm:ss.sss) DECP1= '-18:11:46.20' / Declination of Probe 2(dd:mm:ss.ss) FILTP1= 'S-H' / Filter position of Probe 2 ---Phil Massey, July 11, 2012