PHT generates per detector an SPD record for each signal per chopper plateau or for each raster point. There are 7 separate SPD products:
In order to retain the information on the actual observing conditions, each SPD record contains additional information to identify the operating conditions under which the data were collected. Within an SPD file, the type of record is determined by:
Within one AOT, data of different types can be archived inside the same SPD file. Examples:
The following header keywords are included in all PHT SPD products.
FIELD T Description Comment DETECTOR C Detector subsystem NPIXEL I Number of detector pixels NMEAS I Number of measurements CALSEQU I Calibration sequence PTOREXT C Point(P) or Extended(E) FPCMODE C Focal plane chopper mode see Table 13.2 FPCAMP I Chopper amplitude in arcsec FPCNSTE I Number of chopper steps only if chop mode FPCINCR I Increment between steps (arcsec) only if chop mode DARKPi R dark signal in [V/s] for pixel, both keywords - DARKUPi R dark signal uncertainty -repeated for each pixel
The following header keywords are repeatedly given for each filter
of measurement 
:
FIELD T Description Comment FILTERm C Filter filter name of measurementlog MJy/sr) A0RIm R Reset interval corr. offset, A0 in V/s, see Section 4.3.3 A0RIUm R Uncertainty in A0 in V/s A1RIm R Reset interval corr. slope, A1 A1RIUm R Uncertainty in A1 PFmPiLl R Mean of signal for logical ramp for pixel
= 1
8, see Section 7.5 PDmPiLl R Difference between patterns for logical ramp for pixel
Notes:
The following header keywords are appended after all filters have been listed:
FIELD T Description Comment SATLIMi R Saturation limit in Volts for pixel-for signal deglitching NITERATE I No. of iterations of deglitcher NLOCAL I No. of local points used by deglitcher NSTEP I Deglitcher step size NSIGMA R Deglitcher: rms from local median NBAD I Deglitcher: badness count limit CALFCS I FCS used for cal calculations FCS 1 or 2 RDITER I Ramp deglitch: no. iterations see Section 7.2.9- RDFSIG R Ramp deglitch: sigma for detection -for ramp deglitching RDMINP I Ramp deglitch: min. readouts in ramp DRALPHA R Drift removal: significance level see Section 7.3.5 - DRMINPTS I Drift removal: min. points -for drift recognition READAUTO I Readouts with automatic data reduction READSUSP I Readouts flagged as suspicious READOFFT I Readouts off-target READCOP I Readouts with chopper off position RAMPSAT I Ramps saturated RAMPDEGL I Ramps deglitched RAMPPCT I % ramps accepted RAMPUSET I % time for accepted ramps RAMPINVD I Bad cycles RAMPZSG I Zero signals on plateau plateaux with no accepted signals PLATNORP I Plateaux with no good ramps PLATDROP I Plateaux dropouts due to gaps USEDRS L Use destructive readouts? always `F' for OLP DISCNDRS I Discard 1st NDRs of ramps number of readouts per ramp removed see Section 7.2.2
The following keywords are only present in SPD products from absolute photometry observations with PHT05:
FIELD T Description Comment MEASPW1 R FCS1 heating power in mW POWFCS1 R Power from FCS1 in W RESPR R ratio Actual/Default responsivity CAL R Responsivity used in A/W CALUNC R uncertainty in V/s CALQUAL R FCS quality RESPP1 R FCS responsivity in A/W RUNCP1 R FCS responsivity uncertainty in A/W DRESP1 R Default responsivity in A/W DRUNP1 R Default responsivity uncertainty in A/W COLD R Cold FCS measurement in V/s COLDUNC R Cold FCS uncertainty in V/s
In case of PHT25:
FIELD T Description Comment MEASPW1 R FCS1 heating power in mW POWFCS1 R Power from FCS1 in W RESPPi R FCS responsivity in A/W, for pixel
The following keywords are only present in SPD product of aperture
photometry observations PHT04. The keywords ending with are
repeated for each measurement (aperture) in the observation. Note:
BSRSS stands for `background subtracted relative source signal'.
FIELD T Description Comment BACKSRSS L TRUE if BSRSS processing performed FILTCORF L TRUE if aperture correction available for given filter APERm C Aperture
PHT-P1/2/3 Standard Processed Data where x = 1,2, or 3; is the
aperture number in the measurement sequence.
HEADER
Product specific header entries:
FIELD T Description Comment CALAPm I Aperture used for FCS calibration CHW2 position CAL R Responsivity used in A/W CALUNC R uncertainty in V/s CALQUAL R FCS quality RESPP1 R FCS responsivity in A/W RUNCP1 R FCS responsivity uncertainty in A/W DRESP1 R Default responsivity in A/W DRUNP1 R Default responsivity uncertainty in A/W COLD R Cold FCS measurement signal in V/s COLDUNC R Uncertainty in V/sRECORD
FIELD N T Description Comment GPSCTKEY 1 I*4 Instrument time key GPSCRPID 2 I*1 Raster point ID points and lines GPSCFILL 1 I*2 Filler PPxSKYID 1 I*2 Keyword identifier PPxSMNUM 1 I*2 Measurement number PPxSSPAR 1 I*2 Spare PPxSFILT 1 I*2 Filter ID (CHW3 position) value: 1 - 14, see Appendix A.1 PPxSAPER 1 I*2 Aperture ID (CHW2 position) idem PPxSPOLZ 1 I*2 Polariser ID (CHW1 position) idem PPxSNDRS 1 I*2 Number of destructive readouts per chopper plateau PPxSCSTP 1 I*2 Chopper step number see Section 7.2.5 PPxSDWEL 1 I*4 Chopper dwell time ins, commanded time PPxSMEAS 1 I*4 Measurement time in s PPxSCPOS 1 I*4 Chopper position in arcsec PPxSMNPW 1 R*4 Mean or fitted power in W PPxSMNPU 1 R*4 Uncertainty in W PPxSMDPW 1 R*4 Median power in W PPxSQ1PW 1 R*4 1st quartile of power in W PPxSQ3PW 1 R*4 3rd quartile of power in W PPxSPLEN 1 I*4 Chopper plateau length in
PHT-C100 Standard Processed Data
HEADER
Product specific header entries:
FIELD T Description Comment CALPi R Responsivity used in A/W CALUPi R uncertainty in A/W, for pixelRECORD Record length: 300 bytes
FIELD N T Description Comment GPSCTKEY 1 I*4 Instrument time key GPSCRPID 2 I*1 Raster point ID points and lines GPSCFILL 1 I*2 Filler PC1SKYID 1 I*2 Keyword identifier PC1SMNUM 1 I*2 Measurement number PC1SSPAR 1 I*2 Spare PC1SFILT 1 I*2 Filter ID (CHW3 position) value: 1 - 14, see Appendix A.1 PC1SAPER 1 I*2 Aperture ID (CHW2 position) idem PC1SPOLZ 1 I*2 Polariser ID (CHW1 position) idem PC1SNDRS 1 I*2 Number of destructive readouts PC1SCSTP 1 I*2 Chopper step number see Section 7.2.5 PC1SDWEL 1 I*4 Chopper dwell time in
PHT-C200 Standard Processed Data
HEADER
Product specific header entries:
FIELD T Description Comment CALPi R Responsivity used in A/W CALUPi R uncertainty in A/W, for pixel
RECORD
Record length: 152 bytes
FIELD N T Description Comment GPSCTKEY 1 I*4 Instrument time key GPSCRPID 2 I*1 Raster point ID points and lines GPSCFILL 1 I*2 Filler PC2SKYID 1 I*2 Keyword identifier PC2SMNUM 1 I*2 Measurement number PC2SSPAR 1 I*2 Spare PC2SFILT 1 I*2 Filter ID (CHW3 position) value: 1 - 14, see Appendix A.1 PC2SAPER 1 I*2 Aperture ID (CHW2 position) idem PC2SPOLZ 1 I*2 Polariser ID (CHW1 position) idem PC2SNDRS 1 I*2 Number of destructive readouts PC2SCSTP 1 I*2 Chopper step number PC2SDWEL 1 I*4 Chopper dwell time in
PHT-SS Standard Processed Data
HEADER
Product specific header entries:
FIELD T Description Comment CALDATE C Date cal defaults generated PTOREXT C Point(P) or Extended(E) LAMBDAd C Central wavelength of pixel in m LUNCd C Uncertainty in m STATPIX C Pixel used in statisticsnote:
RECORD
Record length: 1560
FIELD N T Description Comment GPSCTKEY 1 I*4 Instrument time key GPSCRPID 2 I*1 Raster point ID points and lines GPSCFILL 1 I*2 Filler PSSSPOLZ 1 I*2 Polariser ID (CHW1 position) value: 1 - 14, see Appendix A.1 PSSSNDRS 1 I*2 Number of destructive readouts PSSSDWEL 1 I*4 Chopper dwell time in
PHT-SL Standard Processed Data
HEADER
Product specific header entries are the same as for product PSSS.
RECORD
Record of PSLS is identical to that of PSSS.
PPxA (where x=1,2,3) contains the SPD of the FCS measurements obtained with detector P1, P2 or P3. PPxA products are also referred to as Cal-A files (see Section 5.7.2). The product of a chopped measurement contains 1 record per chopper plateau. In case a cold FCS measurement is selected in the absolute photometry AOT PHT05, the first record contains the cold FCS measurement and the second record contains the results of the heated FCS measurement.
RECORD
Record length: 84
FIELD N T Description Comment GPSCTKEY 1 I*4 Instrument time key GPSCRPID 2 I*1 Raster point ID points and lines GPSCFILL 1 I*2 Filler PPxAQFLG 1 I*2 Quality flag PPxAKYID 1 I*2 Keyword identifier PPxAMNUM 1 I*2 Measurement number PPxASPAR 1 I*2 Spare PPxAFILT 1 I*2 Filter ID (CHW3 position) value: 1 - 14, see Appendix A.1 PPxAAPER 1 I*2 Aperture ID (CHW2 position) idem PPxAPOLZ 1 I*2 Polariser ID (CHW1 position) idem PPxASTAT 1 I*2 FPC state 0 = CFOV, 1 = FCS1, 2 = FCS2 PPxADWEL 1 I*4 Commmanded chopper dwell time in
Note: FPC state (PPxASTAT) cannot be zero for these measurements.
PCxA (where x=1 or 2) is a Cal-A product which contains the SPD of the FCS measurements obtained with the C100 or C200 detector arrays. In case a cold FCS measurement is selected in the absolute photometry AOT PHT25, the first record contains the cold FCS measurement and the second record contains the results of the heated FCS measurement.
HEADER
Product specific header entries:
STATPIX I Pixel used in statistics
RECORD
Record length: 316 for x=1, 180 for x=2
FIELD N T Description Comment GPSCTKEY 1 I*4 Instrument time key GPSCRPID 2 I*1 Raster point ID points and lines GPSCFILL 1 I*2 Filler PCxAQFLG 1 I*2 Quality flag PCxAKYID 1 I*2 Keyword identifier PCxAMNUM 1 I*2 Measurement number PCxASPAR 1 I*2 Spare PCxAFILT 1 I*2 Filter ID (CHW3 position) value: 1 - 14, see Appendix A.1 PCxAAPER 1 I*2 Aperture ID (CHW2 position) idem PCxAPOLZ 1 I*2 Polariser ID (CHW1 position) idem PCxASTAT 1 I*2 FPC state 0 = CFOV, 1 = FCS1, 2 = FCS2 PCxADWEL 1 I*4 Chopper dwell time in
For product PC1A the parameters 
and 
are 9 and 3, respectively;
for product PC2A both is 4 and is zero.
Note: FPC state (PCxASTAT) cannot be zero for these measurements.
PPSD contains the SPD of the PHT-SS dark measurement. This measurement is only obtained with AOT PHT40.
RECORD
Record length: 840
FIELD N T Description Comment GPSCTKEY 1 I*4 Instrument time key GPSCRPID 2 I*1 Raster point ID points and lines GPSCFILL 1 I*2 Filler PSSDDARK 64 R*4 Dark signal in V/s PSSDDUNC 64 R*4 Uncertainty in V/s PSSDNSIG 64 R*4 No. of valid signals on the plateau PSSDFLAG 64 I*1 Status Flag
PPSD contains the SPD of the PHT-SL dark measurement. This measurement is only obtained with AOT PHT40.
The record is identical to that of PHT-SS, see Section 13.3.9.
PPxD (where x=1,2,3) contains the SPD of the dark measurements obtained with detector P1, P2 or P3. These measurements are only obtained with AOT PHT05.
RECORD
Record length: 24
FIELD N T Description Comment GPSCTKEY 1 I*4 Instrument time key GPSCRPID 2 I*1 Raster point ID points and lines GPSCFILL 1 I*2 Filler PPxDDARK 1 R*4 Dark signal in V/s PPxDDUNC 1 R*4 Uncertainty in V/s PPxDNSIG 1 I*4 No. of valid signals on the plateau PPxDFLAG 1 I*1 Status Flag PPxDFILI 3 I*1 Filler
PC1D contains the SPD of the dark measurements obtained with detector C100. These measurements are only carried out for AOT PHT25.
RECORD
Record length: 128
FIELD N T Description Comment GPSCTKEY 1 I*4 Instrument time key GPSCRPID 2 I*1 Raster point ID points and lines GPSCFILL 1 I*2 Filler PC1DDARK 9 R*4 Dark signal in V/s PC1DDUNC 9 R*4 Uncertainty in V/s PC1DNSIG 9 I*4 No. of valid signals on the plateau PC1DFLAG 9 I*1 Status Flag PC1DFILI 3 I*1 Filler
PC2D contains the SPD of the dark measurements obtained with detector C200. These measurements are only carried out for AOT PHT25.
RECORD
Record length: 60
FIELD N T Description Comment GPSCTKEY 1 I*4 Instrument time key GPSCRPID 2 I*1 Raster point ID points and lines GPSCFILL 1 I*2 Filler PC2DDARK 4 R*4 Dark signal in V/s PC2DDUNC 4 R*4 Uncertainty in V/s PC2DNSIG 4 I*4 No. of valid signals on the plateau PC2DFLAG 4 I*1 Status Flag
The pixel status flag in the SPD products gives an indication of the data processing quality for each detector pixel. The status flag is one byte of information, the coding of the decimal value of the byte is given in Table 13.3. All success and warning codes are even; all failure (do not process further) codes are odd.
| Decimal | |
| Value | Description |
| 0 | normal (pixel ok) |
| 1 | calibration measurement saturated |
| 2 | plateau partly affected by drift |
| 3 | all ramps on plateau rejected |
| 4 | plateau data affected by residual drift |
| 5 | zero standard deviation |
| 6 | not used |
| 7 | zero signal for plateau |