The following is an example header for a simple case of a single CCD using a single amplifier. The instrument is a direct camera.
SIMPLE = T / FITS format BITPIX = 16 / Number of bits per pixel NAXIS = 2 / Number of image axes OBJECT = 'm51 V 600s' / Observation title OBSTYPE = 'OBJECT ' / Observation type DATE-OBS= '05/04/87' / UTC date of observation MJD-OBS = 46890.394063 / MJD of observation UTC = '09:27:27.00' / UTC of observation LST = '14:53:42.00' / LST of observation RADECSYS= 'FK5 ' / Default coordinate system EQUINOX = 2000.0 / Default coordinate equinox OBJNAME = 'M 51 ' / Target object OBJTYPE = 'galaxy ' / Type of object OBJRA = '13:29:24.00' / Right ascension of object (hours) OBJDEC = '47:15:34.00' / Declination of object (degrees) OBJEPOCH= 1950.0 / Epoch of object coordinates OBSERVAT= 'KPNO ' / Observatory PHOTOMET= 'photometric' / Photometric conditions TELESCOP= '0.9m ' / Telescope TELCONF = 'f13' / Telescope configuration TELTCS = 'TCS V1.0' / Telescope control system TELRA = '13:29:24.00' / Telescope right ascension (hours) TELDEC = '47:15:34.00' / Telescope declination (hours) TELFOCUS= 1430 / Telescope focus CAMERA = 'Direct Camera' / Camera DETECTOR= 'T2KA ' / Detector DEWAR = 'Universal Dewar #2' / Dewar RAPANGL = -90.0 / Position angle of RA axis (degrees) DECPANGL= 0.0 / Position angle of Dec axis (degrees) DETSIZE = '[1:2048,1:2048]' / Detector size CCDSEC = '[1:2048,1:2048]' / Region of CCD read CCDSUM = '1 1 ' / CCD on-chip summing BIASSEC = '[2049:2080,1:2048]' / Bias section DATASEC = '[1:2048,1:2048]' / Data section TRIMSEC = '[1:2048,1:2048]' / Section of useful data EXPTIME = 600 / Exposure time (seconds) DARKTIME= 600 / Dark time (seconds) GAIN = 4.3 / CCD gain (e/ADU) RDNOISE = 12. / Readout noise (e) FILENAME= 'n1020.fit' / Original filename CHECKSUM= '0WDA3T940TA90T99' / Header checksum DATASUM = 'aMmjbMkhaMkhaMkh' / Data checksum CHECKVER= 'complement' / Checksum version OBSERVER= 'G. Jacoby, D. Tody, F. Valdes' / Observers PROPOSER= 'G. Jacoby, D. Tody, F. Valdes' / Proposers PROPOSAL= 'Search for primeval galaxies' / Proposal title PROPID = 'KPNO 12345' / Proposal identification ARCHIVE = 'KPNO STB' / Archive OBSID = 'kpno.36in.870405.257752' / Observation identification IMAGEID = 1 / Image identification KWDICT = 'NOAO FITS Keyword Dictionary: V0.0' / Keyword dictionary
The following examples show the main keywords for the detector geometry for a single CCD using one amplifier and using two amplifiers. The WCS shown is in pixels though this could be given in RA and DEC if the data system allows it.
1. An example for a single CCD with a single amplifier. In this case a simple FITS image is produced rather than a FITS Image extension; i.e. there is only a PHU and it has associated data.
----------------------- PHU ---------------------------------------------------- OBSERVAT= 'KPNO ' / Observatory of observation TELESCOP= '0.9-m ' / Telescope of observation CAMERA = 'CCD DIRECT CAMERA' / Camera OBSID = 'kpno.36in.870405.257752' / Observation identification IMAGEID = 1 / Image identification DETECTOR= 'T2KA ' / Detector of observation DETSIZE = '[1:2048,1:2048]' / Detector size NCCDS = 1 / Number of CCDs in detector DETSEC = '[1:2048,1:2048]' / Section of detector CCDNAME = 'T2KA ' / CCD name CCDSIZE = '[1:2048,1:2048]' / CCD effective size CCDNAMPS= 1 / Number of amplifiers AMPNAME = 'Amplifier 1' / Amplifier identification CCDSUM = '1 1' / On chip summation CCDSEC = '[1:2048,1:2048]' / CCD section read DATASEC = '[1:2048,1:2048]' / Data section in raw image BIASSEC = '[2049:2080,1:2048]' / Bias section in raw image TRIMSEC = '[1:2048,1:2048]' / Trim section definition GAIN = 1.7 / CCD amplifier gain (e/ADU) RDNOISE = 4.3 / CCD amplifier read noise (e) CTYPE1 = 'PIXEL ' / Axis type CTYPE2 = 'PIXEL ' / Axis type CRPIX1 = 1. / Coordinate reference pixel CRPIX2 = 1. / Coordinate reference pixel CRVAL1 = 1. / Coordinate reference value CRVAL2 = 1. / Coordinate reference value CDELT1 = 1. / Coordinate interval CDELT2 = 1. / Coordinate interval
2. An example for a single CCD with two amplifiers. The keywords for the common PHU and for each EHU are shown.
----------------------- PHU ---------------------------------------------------- OBSERVAT= 'KPNO ' / Observatory of observation TELESCOP= '0.9-m ' / Telescope of observation CAMERA = 'CCD DIRECT CAMERA' / Camera OBSID = 'kpno.36in.870405.257752' / Observation identification DETECTOR= 'T2KA ' / Detector of observation DETSIZE = '[1:2048,1:2048]' / Detector size NCCDS = 1 / Number of CCDs in detector ----------------------- EHU 1 -------------------------------------------------- EXTNAME = 'im1 ' / Extension name IMAGEID = 1 / Image identification DETSEC = '[1:2048,1:2048]' / Section of detector CCDNAME = 'T2KA ' / CCD name CCDSIZE = '[1:2048,1:2048]' / CCD effective size CCDNAMPS= 1 / Number of amplifiers AMPNAME = 'Amplifier 1' / Amplifier identification CCDSUM = '1 1' / On chip summation CCDSEC = '[1:1024,1:2048]' / CCD section read DATASEC = '[1:1024,1:2048]' / Data section in raw image BIASSEC = '[1025:1056,1:2048]' / Bias section in raw image TRIMSEC = '[1:1024,1:2048]' / Trim section definition GAIN = 1.7 / CCD amplifier gain (e/ADU) RDNOISE = 4.3 / CCD amplifier read noise (e) CTYPE1 = 'PIXEL ' / Axis type CTYPE2 = 'PIXEL ' / Axis type CRPIX1 = 1. / Coordinate reference pixel CRPIX2 = 1. / Coordinate reference pixel CRVAL1 = 2049. / Coordinate reference value CRVAL2 = 8192. / Coordinate reference value CDELT1 = 1. / Coordinate interval CDELT2 = -1. / Coordinate interval ----------------------- EHU 2 ------------------------------------------------- EXTNAME = 'im2 ' / Extension name IMAGEID = 2 / Image identification DETSEC = '[1:2048,1:2048]' / Section of detector CCDNAME = 'T2KA ' / CCD name CCDSIZE = '[1:2048,1:2048]' / CCD effective size CCDNAMPS= 1 / Number of amplifiers AMPNAME = 'Amplifier 2' / Amplifier identification CCDSUM = '1 1' / On chip summation CCDSEC = '[2048:1025,1:2048]' / CCD section read DATASEC = '[1:1024,1:2048]' / Data section in raw image BIASSEC = '[1025:1056,1:2048]' / Bias section in raw image TRIMSEC = '[1:1024,1:2048]' / Trim section definition GAIN = 1.8 / CCD amplifier gain (e/ADU) RDNOISE = 4.7 / CCD amplifier read noise (e) CTYPE1 = 'PIXEL ' / Axis type CTYPE2 = 'PIXEL ' / Axis type CRPIX1 = 1. / Coordinate reference pixel CRPIX2 = 1. / Coordinate reference pixel CRVAL1 = 2058. / Coordinate reference value CRVAL2 = 1. / Coordinate reference value CDELT1 = -1. / Coordinate interval CDELT2 = 1. / Coordinate interval
The following examples show the main keywords for the detector geometry for a single CCD using one amplifier and using two amplifiers from a 4x2 CCD mosaic of 2048x4096 CCDs. The WCS shown is in pixels for the full 8Kx8K format though it could be given in RA and DEC if the data system allows it.
1. An example for a single CCD with a single amplifier from a CCD mosaic. The keywords from the common PHU (for the whole mosaic) and for the EHU are shown. If all CCDs used a single amplifier the whole mosaic would produce 8 EHUs.
----------------------- PHU ---------------------------------------------------- OBSERVAT= 'KPNO ' / Observatory of observation TELESCOP= '0.9-m ' / Telescope of observation CAMERA = 'CCD DIRECT CAMERA' / Camera OBSID = 'kpno.36in.870405.257752' / Observation identification DETECTOR= 'CCD Mosaic' / Detector of observation DETSIZE = '[1:8192,1:8192]' / Detector size NCCDS = 8 / Number of CCDs in detector ----------------------- EHU ---------------------------------------------------- EXTNAME = 'im1 ' / Extension name IMAGEID = 1 / Image identification DETSEC = '[2049:4096,4097:8192]' / Section of detector CCDNAME = 'CCD Mosaic 6 [2,2]' / CCD name CCDSIZE = '[1:2048,1:4096]' / CCD effective size CCDNAMPS= 1 / Number of amplifiers AMPNAME = 'Amplifier 1' / Amplifier identification CCDSUM = '1 1' / On chip summation CCDSEC = '[1:2048,4096:1]' / CCD section read DATASEC = '[1:2048,1:4096]' / Data section in raw image BIASSEC = '[2049:2080,1:4096]' / Bias section in raw image TRIMSEC = '[1:2048,1:4096]' / Trim section definition GAIN = 1.7 / CCD amplifier gain (e/ADU) RDNOISE = 4.3 / CCD amplifier read noise (e) CTYPE1 = 'PIXEL ' / Axis type CTYPE2 = 'PIXEL ' / Axis type CRPIX1 = 1. / Coordinate reference pixel CRPIX2 = 1. / Coordinate reference pixel CRVAL1 = 2049. / Coordinate reference value CRVAL2 = 8192. / Coordinate reference value CDELT1 = 1. / Coordinate interval CDELT2 = -1. / Coordinate interval
2. An example for a single CCD with two amplifiers from a CCD mosaic. The keywords from the common PHU and for each EHU are shown. If all CCDs used dual amplifiers the whole mosaic would produce 16 EHUs.
----------------------- PHU ---------------------------------------------------- OBSERVAT= 'KPNO ' / Observatory of observation TELESCOP= '0.9-m ' / Telescope of observation CAMERA = 'CCD DIRECT CAMERA' / Camera OBSID = 'kpno.36in.870405.257752' / Observation identification DETECTOR= 'CCD Mosaic 1' / Detector of observation DETSIZE = '[1:8192,1:8192]' / Detector size NCCDS = 8 / Number of CCDs in detector ----------------------- EHU 1 -------------------------------------------------- EXTNAME = 'im1 ' / Extension name IMAGEID = 1 / Image identification DETSEC = '[1:1024,1:4096]' / Section of detector CCDNAME = 'CCD Mosaic 1-6 [2,2]' / CCD name CCDSIZE = '[1:2048,1:4096]' / CCD effective size CCDNAMPS= 2 / Number of amplifiers AMPNAME = 'Amplifier 1' / Amplifier identification CCDSUM = '1 1' / On chip summation CCDSEC = '[1:1024,1:4096]' / CCD section read DATASEC = '[1:1024,1:4096]' / Data section in raw image BIASSEC = '[1025:1056,1:4096]' / Bias section in raw image TRIMSEC = '[1:1024,1:4096]' / Trim section definition GAIN = 1.7 / CCD amplifier gain (e/ADU) RDNOISE = 4.3 / CCD amplifier read noise (e) CTYPE1 = 'PIXEL ' / Axis type CTYPE2 = 'PIXEL ' / Axis type CRPIX1 = 1. / Coordinate reference pixel CRPIX2 = 1. / Coordinate reference pixel CRVAL1 = 2049. / Coordinate reference value CRVAL2 = 8192. / Coordinate reference value CDELT1 = 1. / Coordinate interval CDELT2 = -1. / Coordinate interval ----------------------- EHU 2 ------------------------------------------------- EXTNAME = 'im2 ' / Extension name IMAGEID = 2 / Image identification DETSEC = '[1025:2048,1:4096]' / Section of detector CCDNAME = 'CCD Mosaic 6 [2,2]' / CCD name CCDSIZE = '[1:2048,1:4096]' / CCD effective size CCDNAMPS= 2 / Number of amplifiers AMPNAME = 'Amplifier 2' / Amplifier identification CCDSUM = '1 1' / On chip summation CCDSEC = '[2048:1025,1:4096]' / CCD section read DATASEC = '[1:1024,1:4096]' / Data section in raw image BIASSEC = '[1025:1056,1:4096]' / Bias section in raw image TRIMSEC = '[1:1024,1:4096]' / Trim section definition GAIN = 1.8 / CCD amplifier gain (e/ADU) RDNOISE = 4.7 / CCD amplifier read noise (e) CTYPE1 = 'PIXEL ' / Axis type CTYPE2 = 'PIXEL ' / Axis type CRPIX1 = 1. / Coordinate reference pixel CRPIX2 = 1. / Coordinate reference pixel CRVAL1 = 4046. / Coordinate reference value CRVAL2 = 8192. / Coordinate reference value CDELT1 = -1. / Coordinate interval CDELT2 = -1. / Coordinate interval