The following is a list of the headers and arrays found in GSD format (version 5.3) files in the order in which they appear in the file. Listed is the NRAO name, JCMT name, data type, description for each element. In addition, the dimensionality of the arrays for various observation types (Normal, Total Power, Continuous Calibration, Cross Correlation) is given (for scalar headers, the table indicates for which observation types the headers were used).
NRAO name | JCMT name | Data type | Description |
C1TEL | TEL_NAME | char* | Telescope name |
C1PID | PROJECT | char* | Identifies the observing program |
C1OBS | PROJECT_OBS_1 | char* | Name of the primary observer |
C1ONA1 | PROJECT_OBS_2 | char* | Name of the support scientist |
C1ONA2 | PROJECT_OBS_3 | char* | Name of the telescope operator |
C1SNA1 | CENTRE_NAME_1 | char* | Source name part 1 |
C1SNA2 | CENTRE_NAME_2 | char* | Source name part 2 or altern. name |
C4CSC | CENTRE_COORDS | char* | Character code of commanded centre or source coordinate system |
C4CECO | CENTRE_CODE | int | Centre coords. AZ=1; EQ=3; RD=4; RB=6; RJ=7; GA=8 |
C4EPT | EPOCH_TYPE | char* | Type of epoch, JULIAN, BESSELIAN or APPARENT |
C4MCF | CENTRE_MOVING | char | Centre moving flag (solar system object) |
C4EPH | CENTRE_EPOCH | double | Date of the RA |
C4ERA | CENTRE_RA1950 | double | Right ascension of source for EPOCH |
C4EDEC | CENTRE_DEC1950 | double | Declination of source for EPOCH |
C4RADATE | CENTRE_RA | double | Right Ascension of date |
C4DECDATE | CENTRE_DEC | double | Declination of date |
C4RA2000 | CENTRE_RA2000 | double | Right ascension J2000 |
C4EDEC2000 | CENTRE_DEC2000 | double | Declination J2000 |
C4GL | CENTRE_GL | double | Galactic longitude |
C4GB | CENTRE_GB | double | Galactic latitude |
C4AZ | CENTRE_AZ | double | Azimuth at observation date |
C4EL | CENTRE_EL | double | Elevation at observation date |
C4LSC | CELL_COORDS | char* | har. code for local x-y coord.system |
C6FC | CELL_CODE | int | Local x-y AZ=1; EQ=3; RD=4; RB=6; RJ=7; GA=8 |
C4ODCO | CELL_UNIT | char* | Units of cell and mapping coordinates;offset definition code |
C6DX | CELL_X | double | Cell x dim,; descriptive origin item 1 |
C6DY | CELL_Y | double | Cell y dimension; descriptive origin item 2 |
C6MSA | CELL_V2X | double | Scanning angle - angle from local vertical to x axis measured CW |
CELL_V2Y | CELL_V2Y | double | Position angle of cell y axis (CCW) |
C4AXY | CELL_X2Y | double | Angle between cell y axis and x-axis (CCW) |
C4SX | CENTRE_OFFSET_X | double | Commanded x centre position (JCMT cells wrt to centre; NRAO abs. degrees) |
C4SY | CENTRE_OFFSET_Y | double | Commanded y centre position (JCMT cells wrt to centre; NRAO abs. degrees) |
C4RX | REFERENCE_X | double | Reference x position (JCMT cells wrt to centre; NRAO abs. degrees) |
C4RY | REFERENCE_Y | double | Reference y position (JCMT cells wrt to centre; NRAO abs. degrees) |
C1HGT | TEL_HEIGHT | double | Height of telescope above sea level |
C1LONG | TEL_LONGITUDE | double | Geographical longitude of telescope (West +ve) |
C1LAT | TEL_LATITUDE | double | Geodetic latitude of telescope (North +ve) |
C1SNO | NOBS | double | Observation number |
C6ST | OBS_TYPE | char* | Type of observation |
C1RCV | FRONTEND | char* | Name of the frontend |
C1FTYP | FE_TYPE | char* | Type of frontend |
C1BKE | BACKEND | char* | Name of the backend |
C1BTYP | BE_TYPE | char* | Type of backend |
C3DAT | OBS_UT1D | double | UT1 date of observation |
C3UT | OBS_UT1H | double | UT1 hour of observation |
C3UT1C | OBS_UT1C | double | UT1-UTC correction interpolated from time service telex (in days) |
C3LST | OBS_LST | double | Local sidereal time at the start of the observation |
C3CAL | OBS_CALIBRATION | char | Calibration observation? |
C3CEN | OBS_CENTRE | char | Centre moves between scans? |
C3FLY | OBS_CONTINUOUS | char | Data taken on the fly or in discrete mode? |
C3FOCUS | OBS_FOCUS | char | Focus observation? |
C3MAP | OBS_MAP | char | Map observation? |
C3NPP | NO_MAP_DIMS | int | Number of dimension in the map table |
C3NMAP | NO_MAP_PNTS | int | Number of map points |
C6XNP | NO_X_MAP_PNTS | int | X map dimension; number of points in the x-direction |
C6YNP | NO_Y_MAP_PNTS | int | Y map dimension; number of points in the y-direction |
C6XGC | X_MAP_START | float | X coordinate of the first map point |
C6YGC | Y_MAP_START | float | Y coordinate of the first map point |
C6REV | SCAN_REVERSAL | char | Map rows scanned in alternate directions? |
C6SD | OBS_DIRECTION | char* | Map rows are in X (horizontal) or Y(vertical) direction |
C6XPOS | X_MAP_POSITIVE | char | In first row x increases (TRUE) or decreases (FALSE) |
C6YPOS | Y_MAP_POSITIVE | char | In first row y increases (TRUE) or decreases (FALSE) |
C3NIS | NO_SCANS | int | Number of scans |
C3NSAMPLE | NSCAN | int | Number of scans done |
C3NO_SCAN_VARS1 | NO_SCAN_VARS1 | int | Number of scan table 1 variables |
C3NO_SCAN_VARS2 | NO_SCAN_VARS2 | int | Number of scan table 2 variables |
C3SRT | SCAN_TIME | int | Total time of scan (=total integration time if OBS_CONTINUOUS = .FALSE.) |
C3MXP | NO_SCAN_PNTS | int | Maximum number of map points done in a phase |
C3NCI | NO_CYCLES | int | Maximum number of cycles in the scan |
C3NCYCLE | NCYCLE | int | Number of cycles done in the scan |
C3CL | CYCLE_TIME | int | Duration of each cycle |
C3NCP | NO_CYCLE_PNTS | int | Total number of xy positions observed during a cycle |
C6NP | NCYCLE_PNTS | int | Number of sky points completed in the observation |
C3NSV | NO_PHASE_VARS | int | Number of phase table variables |
C3PPC | NO_PHASES | int | Number of phases per cycle |
C5AT | TAMB | double | Ambient temperature |
C5PRS | PAMB | double | Mean atmospheric pressure |
C5RH | HAMB | double | Mean atmospheric relative humidity |
C4AZERR | SDIS(7) | double | DAZ:Net Az offset at start (inc.tracker ball setting and user correction) |
C4ELERR | SDIS(8) | double | DEL:Net El offset at start (inc.tracker ball setting and user correction) |
UAZ | SDIS(36) | double | User az correction |
UEL | SDIS(37) | double | User el correction |
C7SZVRAD | SZVRAD | int | Number of elements of vradial array |
C8AAE | APERTURE_EFF | double | Ratio total power observed |
C8ABE | BEAM_EFF | double | Fraction of beam in diffraction limited main beam |
C8GN | ANTENNA_GAIN | double | Antenna gain |
C8EL | ETAL | double | Rear spillover and scattering efficiency |
C8EF | ETAFSS | double | Forward spillover and scattering efficiency |
C4SM | CHOPPING | char | Secondary mirror is chopping |
C4FUN | WAVEFORM | char* | Secondary mirror chopping waveform |
C4FRQ | FREQUENCY | float | Secondary mirror chopping period |
C4SMCO | COORDS | char* | Secondary mirror chopping coordinate system |
C4THROW | THROW | float | Secondary mirror chop throw |
C4POSANG | POSANG | float | Secondary mirror chop position angle |
C4OFFS_EW | OFFS_EW | float | Secondary mirror offset parallel to lower axis (East-West Tilt) |
C4OFFS_NS | OFFS_NS | float | Secondary mirror offset parallel to upper axis (North-South Tilt) |
C4X | X | float | Secondary mirror absolute X position at observation start |
C4Y | Y | float | Secondary mirror absolute Y position at observation start |
C4Z | Z | float | Secondary mirror absolute Z position at observation start |
C4EW_SCALE | EW_AMPL_SCALE | float | Secondary mirror ew chop scale |
C4NS_SCALE | NS_AMPL_SCALE | float | Secondary mirror ns chop scale |
C4EW_ENCODER | AMPL_E_SET | int | Secondary mirror ew encoder value |
C4NS_ENCODER | AMPL_N_SET | int | Secondary mirror ns encoder value |
C2FV | DX | float | Secondary mirror x displacement from nominal at observation start |
C2FL | DY | float | Secondary mirror y displacement from nominal at observation start |
C2FR | DZ | float | Secondary mirror z displacement from nominal at observation start |
C4MOCO | TEL_COORDS | char* | Mounting of telescope; defined as LOWER |
C3NFOC | NO_FE_O_CH | int | NO_FE_O_CH:No. of frontend output channels |
C7VR | VELOCITY | double | Radial velocity of the source |
C12TCOLD | T_COLD | float | Cold load temperature |
C12TAMB | T_HOT | float | Ambient load temperature |
C12VDEF | VEL_DEFN | char* | Velocity definition code - radio, optical, or relativistic |
C12VREF | VEL_REF | char* | Velocity frame of reference - LSR, Bary-, Helio-, or Geo- centric |
C3NRC | NO_BE_I_CH | int | Number of backend input channels |
C3NCH | NO_BE_O_CH | int | Number of backend output channels |
C3NRS | NO_BES | int | Number of backend sections |
C7BCV | BAD_CHANNEL | float | Bad channel value |
C12CAL | DATA_UNITS | char* | Units of spectrum data |
C6MODE | SWITCH_MODE | char* | Observation mode |
C12CALTASK | BE_CAL_TASK | char* | Calibration instrument used (FE, BE, or USER) |
C12CALTYPE | BE_CAL_TYPE | char* | Type of calibration (THREELOADS or TWOLOADS) |
C12REDMODE | BE_RED_MODE | char* | Way of calibrating the data (RATIO or DIFFERENCE) |
C3NOIFPBES | NO_IF_PER_BES | int | Number of IF inputs to each section (2 for correlator, 1 for AOS) |
C3CONFIGNR | DAS_CONF_NR | int | Backend configuration |
C3DASOUTPUT | DAS_OUTPUT | char* | Description of output in DAS DATA (SPECTRUM, T_REC, T_SYS, etc.) |
C3DASCALSRC | DAS_CAL_SOURCE | char* | DAS calibration source for backend calibration (POWER or DATA) |
C3DASSHFTFRAC | DAS_SHIFT_FRAC | float | DAS calibration source for backend calibration (POWER or DATA) |
C7TAU225 | CSO_TAU | float | CSO tau at 225GHz |
C7TAURMS | CSO_TAU_RMS | float | CSO tau rms |
C7TAUTIME | CSO_YYMMDDHHMM | char* | CSO tau time (YYMMDDHHMM) |
C7SEEING | SAO_SEEING | float | Seeing at JCMT |
C7SEETIME | SAO_YYMMDDHHMM | char* | SAO seeing time (YYMMDDHHMM) |
C3POLARITY | C3POLARITY | char* | Frontend Polarity |
C3SBMODE | C3SBMODE | char* | Sideband mode |
C55NPH | DAS_NO_PHASE | int | DAS number of phases for interferometry observing |
C55NCYC | DAS_NO_CYCLES | int | DAS number of phases for interferometry observing |
C55NINT | DAS_NINTCYCLE | int | DAS number of phases for interferometry observing |
C55NCORR | DAS_NCORRCYCLE | int | DAS number of correlation cycles |
C55DASPRBIT | DAS_PROC_BITS | int | DAS data processing done |
C55DASPRLOC | DAS_PROC_LOC | char* | Description of where processing is done |
C55LX | RXJ.LX | double | RXJ X length of projected baseline in metres |
C55LY | RXJ.LY | double | RXJ Y length of projected baseline in metres |
C55LZ | RXJ.LZ | double | RXJ Z length of projected baseline in metres |
C55A | RXJ.A | double | RXJ Coefficient of sin term in expression for fringe rate (metres) |
C55B | RXJ.B | double | RXJ Coefficient of cos term in expression for fringe rate (metres) |
C55C | RXJ.C | double | RXJ Coefficient of constant term in expression for fringe rate (metres) |
C55CSOSW | RXJ.CSO_SWITCH | int | RXJ Delay setting of RXJ micro for CSO side |
C55JCMTSW | RXJ.JCMT_SWITCH | int | RXJ Delay setting of RXJ micro for JCMT side |
C55SECOND | RXJ.NSECS | int | RXJ Number of the tick on which integration started |
C55ABSORB | RXJ.ABSORB | char* | CSO Position of absorber IN or OUT |
C55TAU | RXJ.CSO_TAU | float | CSO TAU value |
C55DAZ | RXJ.DAZ | float | CSO Position offset in az (arcsec) |
C55DEL | RXJ.DEL | float | CSO Position offset in elevation (arcsec) |
C55RA | RXJ.RA | double | CSO RA |
C55DEC | RXJ.DEC | double | CSO Dec |
C55EPOCH | RXJ.EPOCH | double | CSO Epoch of CSO RA and Dec |
C55PAZ | RXJ.PAZ | float | CSO Pointing offset in az (arcsec) |
C55PEL | RXJ.PEL | float | CSO Pointing offset in el (arcsec) |
C55TRACK | RXJ.TRACK | char* | CSO Track mode of telescope Y or N |
C55FMODE | RXJ.FMODE | char* | CSO Focus mode of CSO |
C55FX | RXJ.FX | float | CSO X position of focus |
C55FY | RXJ.FY | float | CSO Y position of focus |
C55FZ | RXJ.FZ | float | CSO Z position of focus |
C55VLSR | RXJ.VLSR | float | CSO LSR velocity of source (km/s) |
C55VOFF | RXJ.COFF | float | CSO velocity offset (km/s) |
C55VRAD | RXJ.VRAD | float | CSO radial velocity (km/s) |
C55PLOCK | RXJ.PLOCK | char* | CSO Phase lock status L or U |
C55RFREQ | RXJ.RFREQ | double | CSO Rest frequency of line (GHz) |
C55IFFREQ | RXJ.IFFREQ | double | CSO IF frequency (GHz) |
C55LOFREQ | RXJ.LOFREQ | double | CSO LO frequency (GHz) |
C55FREQOFF | RXJ.FREQOFF | double | CSO frequency offset (GHz) |
C55SIDEBAND | RXJ.SIDEBAND | char* | CSO Sideband U or L |
C55MHN | RXJ.MHN | int | CSO Multiplier Harmonic number |
C55CSOSTATUS | RXJ.CSO_STATUS | int | CSO overall status 0 = bad 1 = good |
C55TELAZ | TEL.SDIS(9) | double | CENTRE_AZ from tel sdis array |
C55TELEL | TEL.SDIS(10) | double | CENTRE_EL from tel sdis array |
NRAO name | JCMT name | Data type | Description |
C55FENUOBS | FE_NUOBS | double | Observing frequencies |
C55FESBSIGN | FE_SB_SIGN | int | FE sideband signs |
C55FENULO | FE_NULO | double | FE LO frequencies |
C7VRADIAL | C7VRADIAL | double | Array for computer radial velocities |
C12SCAN_VARS1 | SCAN_VARS1 | char* | Names of the cols. of scan table1 |
C12SCAN_VARS2 | SCAN_VARS2 | char* | Names of the cols. of scan table2 |
C12SCAN_TABLE_1 | SCAN_TABLE1 | float | Begin scan table |
C12SCAN_TABLE_2 | SCAN_TABLE2 | float | End scan table |
C14PHIST | MAP_TABLE | float | List of xy offsets for each scan |
C11VD | PHASE_VARS | char* | Names of the cols. of phase table |
C11PHA | PHASE_TABLE | float | Phase table: switching scheme dependent |
C12CM | BES_CORR_MODE | int | Correlation function mode |
C12BM | BES_BITMODE | int | Correlation bit mode |
C3OVERLAP | BES_OVERLAP | float | Subband overlap |
C3MIXNUM | DAS_MIXER | int |
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C3BESCONN | BES_CONN | int | BE input channels connected to this section |
C3BEINCON | BE_IN_CONN | int | IF output channels connected to BE input channels |
C3LSPC | NO_BES_O_CH | int | Number of channels per backend section |
C3BESSPEC | BES_SPECTRUM | int | Subsystem nr to which each backend section belongs. |
C12CF | BES_NUOBS | double | Centre frequencies (rest frame of source) [GHz] |
C12RF | BES_NUREST | double | Rest frequency [GHz] |
C3BEFENULO | BES_FE_NULO | double | Copy of frontend LO frequency per backend section |
C3BETOTIF | BES_TOT_IF | double | Total IF per backend section |
C3BEFESB | BES_FE_SB_SIGN | int | Copy of frontend sideband sign per backend section |
C12INFREQ | BE_NUIN | double | BE input frequencies [GHz] |
C12FR | BES_DELTANU | float | Frequency resolution [MHz] |
C12BW | BES_BANDWIDTH | float | Bandwidth [MHz] |
C12RT | BES_T_REC | float | Receiver temperature |
C12SST | BES_T_SYS | float | System temperature |
C12TSKY | BES_T_SKY | float | Sky temperature at last calibration |
C12TTEL | BES_T_TEL | float | Telescope temp. from last skydip |
C12GAINS | BES_GAIN | float | Gain value (kelvins per volt or equivalent) |
C12CT | BES_T_TEL | float | Calibration temperature |
C12WO | BES_T_TEL | float | Water opacity |
C12ETASKY | BES_ETA_SKY | float | Sky transmission from last calibration |
C12ALPHA | BES_ALPHA | float | Ratio of signal sideband to image sideband sky transmission |
C12GS | BES_G_S | float | Normalizes signal sideband gain |
C12ETATEL | BES_ETA_TEL | float | Telescope transmission |
C12TSKYIM | BES_T_SKY_IM | float | Frontend-derived Tsky, image sideband |
C12ETASKYIM | BES_ETA_SKY_IM | float | Frontend-derived sky transmission |
C12TSYSIM | BES_T_SYS_IM | float | Frontend-derived Tsys, image sideband |
C12TASKY | BES_TA_SKY | float | Ratio of signal sideband to image sideband sky transmission |
C3INTT | INTGRN_TIME | int | Scan integration time |
C13DAT | DATA | float | Spectrum data |
C55HOTPOWER | DAS_HOT_POWER | float | Total power measurement on hot load |
C55SKYPOWER | DAS_SKY_POWER | float | Total power measurement on hot load (??) |
C55SAM | SAMPLES | float | Samples to store for cross_correlation mode |
C55POWER | DAS_POWER | float | Total power measurement per subband per integration |
NRAO name | Dims (normal) | Dims (total power) | Dims (cont. cal) | Dims (cross corr.) |
C55FENUOBS | N/A | C3NFOC |
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C55FESBSIGN | N/A | C3NFOC |
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C55FENULO | N/A | C3NFOC |
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C7VRADIAL | C7SZVRAD | N/A | C7SZVRAD | N/A |
C12SCAN_VARS1 | ||||
C12SCAN_VARS2 | ||||
C12SCAN_TABLE_1 | ||||
C12SCAN_TABLE_2 | ||||
C14PHIST | ||||
C11VD | ||||
C11PHA | ||||
C12CM | ||||
C12BM | ||||
C3OVERLAP | ||||
C3MIXNUM | ||||
C3BESCONN | ||||
C3BEINCON | ||||
C3LSPC | ||||
C3BESSPEC | ||||
C12CF | ||||
C12RF | ||||
C3BEFENULO | ||||
C3BETOTIF | ||||
C3BEFESB | ||||
C12INFREQ | ||||
C12FR | ||||
C12BW | ||||
C12RT | ||||
C12SST | C3NRS | C3NRS C3NIS | C3NRS |
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C12TSKY | C3NRS | C3NRS C3NIS | C3NRS |
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C12TTEL | ||||
C12GAINS | ||||
C12CT | ||||
C12WO | ||||
C12ETASKY | C3NRS | C3NRS C3NIS | C3NRS |
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C12ALPHA | ||||
C12GS | ||||
C12ETATEL | ||||
C12TSKYIM | C3NRS | C3NRS C3NIS | C3NRS |
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C12ETASKYIM | C3NRS | C3NRS C3NIS | C3NRS |
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C12TSYSIM | C3NRS | C3NRS C3NIS | C3NRS |
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C12TASKY | C3NRS | C3NRS C3NIS | C3NRS |
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C3INTT | ||||
C13DAT | ||||
C55HOTPOWER | N/A | C3NRS C3NOIFPBES |
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C55SKYPOWER | N/A | C3NRS C3NOIFPBES |
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C55SAM | N/A | C3NCH C55NPH C3NCI |
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C55POWER | N/A | C3NRS C3NOIFPBES C55NPH C3PPC C3NCI | N/A | C3NRS C3NOIFPBES C55NPH C3NCI |