Section 4. High Resolution Spectrograph
The calibration of HRS data consists of the following steps:
1. Bad or suspect data are identified u sing the data quality initialization file, < unique name>.R5H.
2. Raw counts are converted to count rates by dividing each data point by the exposure time.
3. Diode nonlinearities are removed by applying a paired-pulse or dead time correction using coefficients stored in the table <unique name>.CMG.
4. The nonuniformities are removed by using the diode response for each diode stored in reference file <unique name>.R0H. 5. Photocathode granularities are removed by first mapping each data point from detector coordinates to photocathode coordinates using coefficients in tables <unique name>.CZ1 and < unique name>.CZ2. The photocathode response applied is obtained from the reference file <unique name>.R1H.
6. Vignetting correction corrects for both light loss due to vignetting and low-frequency sensitivity variations across the photocathode. The vignetting file has a name of the form <unique name>.R2H.
7. Wavelengths are determined for each point using the dispersion coefficients in table <unique name>.CZ6, correcting for thermal effects using coefficients in table < unique name>.CZ7. For the echelle spectra, the spectral order is computed using the parameters in table < unique name >.CZ5. If necessary, an incidence angle offset is added to the wavelengths. The offset is computed using coefficients stored in table < unique name>.CZ8. A velocity correction is done to convert to heliocentric wavelengths, and a vacuum-to-air correction is performed for wavelengths above 2000 Angstroms.
8. The background is smoothed by a median filter, a mean filter, or a low-order polynomialwith filter widths and polynomial order specified in table < unique name >.CZ3. If the background is a sky spectrum, it is normalized to the object spectrum aperture before subtraction from the gross spectrum using relative aperture sizes also stored in this table. The background is corrected for scattered light using coefficients specified in table <unique name>.CZB. Alternatively, the background can be computed based upon a count rate model instead of data acquired during the observation. The count rate model is specified in table < unique name>.CZE. An ancillary file needed to use the count rate model that is used to issue warnings when the observation is near the SAA is specified in the image <unique name>.R6H.
9. A ripple correction is performed for data taken with an echelle using coefficients in tables <unique name>.CZ9 and <unique name>.CZA.
10. The net flux is converted to absolute flux units using the sensitivity values stored in reference files <unique name>.R3H and <unique name>.R4H.
4.1 HRS Reference Files
The HRS reference files are composed of a FITS header file and a binary data file. Although the header files do follow the FITS conventions, the header listings in this section do not adhere precisely to these conventions. In the header listings contained in this section, beware of the following:
The single quotes required around character strings have been omitted.
Numerical values have not been right justified.
The third column in the listing denoting the variable type is additional information, not part of the FITS header itself.
4.1.1 Diode Response Files (DIO): <unique name>.R0H
Nonuniformities in diode responses for HRS detectors require science data to be normalized using data from the diode response files.
Format: Diode response data files contain a single group of normalization data with 512 entries corresponding to the 512 diodes of each HRS detector. Diode responses are stored in REAL*4 format.
Flags and Indicators: The diode response data file is selected on the basis of the DETECTOR keyword. Restrictions: The HRS calibration software will reject any inappropriately sized groups. The following listing shows a sample diode response image header.
SIMPLE = F / image conforms to the fits standard L1
BITPIX = 32 / bits per data value I2
DATATYPE= REAL*4 / datatype of the group array CHR
NAXIS = 1 / number of data axes I2
NAXIS1 = 512 / words per group I2
GROUPS = T / image is in group format L1
GCOUNT = 1 / number of groups I2
PCOUNT = 0 / number of group parameters I2
PSIZE = 0 / bits in the group parameter block I2
/ HRS DATA DESCRIPTOR KEYWORDS
INSTRUME= HRS / instrument CHR
FILETYPE= DIODE RESPONSE / diode response file set CHR
HEADNAME= / reference file set header filename CHR
DATANAME= / reference file set data filename CHR
DATE = / date this file was written CHR
/ HRS DATA REDUCTION KEYWORDS
DETECTOR= / detector: 1,2 I2
/ HRS DATA QUALITY KEYWORDS
USEAFTER= / use this file for obs. taken on/after this date CHR
PEDIGREE= / data source (INFLIGHT,GROUND,MODEL,DUMMY) & date CHR
DESCRIP = / description of reference data CHR
END
[Listing Version 01 6-JUN-1995]
4.1.2 Photocathode Response Files (PHC): < unique name>.R1H
Nonuniformities in the responses of the photocathodes of the HRS detectors require science data to be normalized using data from the photocathode response files.
Format: Photocathode response files contain multiple groups of responses. Each group contains the responses for a particular line position. Within the group, responses are ordered by equally spaced sample positions determined by the keywords SAMPBEG and SAMPOFF. Photocathode responses are stored as REAL*4 values.
Flags and Indicators: The photocathode response data file is selected on the basis of the GRATING keyword.
The following listing shows a sample image header from a photocathode response data file.
SIMPLE = F / image conforms to the fits standard L1
BITPIX = 32 / bits per data value I2
DATATYPE= REAL*4 / datatype of the group array CHR
NAXIS = 1 / number of data axes I2
NAXIS1 = / words per group I2
GROUPS = T / image is in group format L1
GCOUNT = / number of groups I2
PCOUNT = 1 / number of group parameters I2
PSIZE = 32 / bits in the group parameter block I2
PTYPE1 = LINE_POS / line position CHR
PDTYPE1 = REAL*4 / datatype of parameter 1 CHR
PSIZE1 = 32 / number of bits in parameter 1 I2
/ HRS DATA DESCRIPTOR KEYWORDS
INSTRUME= HRS / instrument CHR
FILETYPE= CATHODE RESPONSE / photocathode response file set CHR
HEADNAME= / reference file set header filename CHR
DATE = / date this file was written CHR
/ HRS DATA REDUCTION KEYWORDS
GRATING = / grating, echelle or mirror in use CHR
APERTURE= / aperture name SSA, LSA CHR
SAMPBEG = / first response sample number R4
SAMPOFF = / response sample number offset R4
/ HRS DATA QUALITY KEYWORDS
USEAFTER= / use thisfile for obs.taken on/afterthis date CHR
PEDIGREE= / data source(INFLIGHT,GROUND,MODEL,DUMMY)&date CHR
DESCRIP = / description of reference data CHR
END
[Listing Version 01 26-AUG-1997]
4.1.3 Vignetting Files (VIG): <unique name>.R2H
The removal of vignetting and wavelength-dependent photocathode variations is done using data from the vignetting files.
Format: Vignetting correction files contain multiple groups of responses. Each group contains the responses for a particular carrousel position and line position. Within the group, responses are ordered by equally spaced sample positions determined by the keywords SAMPBEG and SAMPOFF. Data in the vignetting correction data files are stored in REAL*4 format.
Flags and Indicators: The vignetting response data file is selected on the basis of the GRATING keyword.
The following listing shows a sample HRS vignetting response file.
SIMPLE = F / image conforms to the fits standard L1
BITPIX = 32 / bits per data value I2
DATATYPE= REAL*4 / datatype of the group array CHR
NAXIS = 1 / number of data axes I2
NAXIS1 = / words per group I2
GROUPS = T / image is in group format L1
GCOUNT = / number of groups I2
PCOUNT = 3 / number of group parameters I2
PSIZE = 96 / bits in the group parameter block I2
/ GROUP PARAMETERS: PODPS CALIBRATION
PTYPE1 = CAR_POS / carrousel position CHR
PDTYPE1 = REAL*4 / datatype of parameter 1 CHR
PSIZE1 = 32 / number of bits in parameter 1 I2
PTYPE2 = LINE_POS / line position CHR
PDTYPE2 = REAL*4 / datatype of parameter 2 CHR
PSIZE2 = 32 / number of bits in parameter 2 I2
PTYPE3 = APERTURE / aperture name: SSA, LSA CHR
PDTYPE3 = CHARACTER*4 / datatype of parameter 3 CHR
PSIZE3 = 32 / number of bits in parameter 3 I2
/ HRS DATA DESCRIPTOR KEYWORDS
INSTRUME= HRS / instrument CHR
FILETYPE= VIGNETTING / vignetting calibration file set CHR
HEADNAME= / reference file set header filename CHR
DATANAME= / reference file set data filename CHR
DATE = / date this file was written CHR
/ HRS DATA REDUCTION KEYWORDS
GRATING = / grating, echelle or mirror in use CHR
SAMPBEG = / first response sample number R4
SAMPOFF = / response sample number offset R4
/ HRS DATA QUALITY KEYWORDS
PEDIGREE= / data source (INFLIGHT,GROUND,MODEL,DUMMY) & date CHR
DESCRIP = / description of reference data CHR
END [Listing Version 01 6-JUN-1995]
4.1.4 Absolute Sensitivity Files (ABS): <unique name>.R3H
The absolute sensitivity scale files contain data that are used to perform HRS absolute flux calibration. These files are used in conjunction with the HRS wavelength net files that specify the wavelength net (grid) used for interpolation of absolute sensitivity scale values.
Format: Absolute sensitivity files contain two groups of data that correspond to the large and small apertures of the HRS. Because the HRS wavelength net files contain the wavelength net corresponding to these sensitivity values, it is not assumed that the spacing between wavelength values is uniform. Data in the absolute sensitivity files are stored in REAL*4 format.
Flags and Indicators: The absolute sensitivity data file is selected on the basis of the GRATING keyword.
Restrictions: The HRS calibration software will reject any inappropriately sized groups. The following listing shows a sample HRS absolute sensitivity file.
SIMPLE = F / image conforms to the fits standard L1
BITPIX = 32 / bits per data value I2
DATATYPE= REAL*4 / datatype of the group array CHR
NAXIS = 1 / number of data axes I2
NAXIS1 = / words per group I2
GROUPS = T / image is in group format L1
GCOUNT = 2 / number of groups I2
PCOUNT = 1 / number of group parameters I2
PSIZE = 32 / bits in the group parameter block I2
/ GROUP PARAMETERS: PODPS CALIBRATION
PTYPE1 = APERTURE / aperture name: SSA, LSA CHR
PDTYPE1 = CHARACTER*4 / datatype of parameter 1 CHR
PSIZE1 = 32 / number of bits in parameter 1 I2
/ HRS DATA DESCRIPTOR KEYWORDS
INSTRUME= HRS / instrument CHR
FILETYPE= ABSOLUTE FLUX / absolute flux calibration file set CHR
HEADNAME= / reference file set header filename CHR
DATANAME= / reference file set data filename CHR
DATE = / date this file was written CHR
/ HRS DATA REDUCTION KEYWORDS
GRATING = / grating, echelle or mirror in use CHR
/ HRS DATA QUALITY KEYWORDS
USEAFTER= / use this file for obs. taken on/after this date CHR
PEDIGREE= / data source (INFLIGHT,GROUND,MODEL,DUMMY) & date CHR
DESCRIP = / description of reference data CHR
END
[Listing Version 01 6-JUN-1995]
4.1.5 Wavelength Net Files (NET): <unique name>.R4H
The wavelength net files contain data that are used to perform HRS absolute flux calibration. These data provide the nonuniform interpolation net (grid) used to compute an absolute sensitivity scale from data in the HRS absolute sensitivity files.
Format: Wavelength net files contain two groups of data that correspond to the large and small apertures of the HRS. Because the HRS absolute sensitivity files contain the absolute sensitivities corresponding to the wavelength net values, these two sets of files have exactly the same structure. Data in the wavelength net files are stored in REAL*4 format.
Flags and Indicators: The wavelength net data file is selected on the basis of the GRATING keyword.
Restrictions: The HRS calibration software will reject any inappropriately sized groups. The following listing shows a sample HRS wavelength net file.
SIMPLE = F / image conforms to the fits standard L1
BITPIX = 32 / bits per data value I2
DATATYPE= REAL*4 / datatype of the group array CHR
NAXIS = 1 / number of data axes I2
NAXIS1 = / words per group I2
GROUPS = T / image is in group format L1
GCOUNT = 2 / number of groups I2
PCOUNT = 1 / number of group parameters I2
PSIZE = 32 / bits in the group parameter block I2
/ GROUP PARAMETERS: PODPS CALIBRATION
PTYPE1 = APERTURE / aperture name: SSA, LSA CHR
PDTYPE1 = CHARACTER*4 / datatype of parameter 1 CHR
PSIZE1 = 32 / number of bits in parameter 1 I2
/ HRS DATA DESCRIPTOR KEYWORDS
INSTRUME= HRS / instrument CHR
FILETYPE= WAVELENGTH NET / absolute flux wavelength net file set CHR
HEADNAME= / reference header file name CHR
DATANAME= / reference data file name CHR
DATE = / date this file was written CHR
/ HRS DATA REDUCTION KEYWORDS
GRATING = / grating, echelle or mirror in use CHR
/ HRS DATA QUALITY KEYWORDS
USEAFTER= / use this file for obs. taken on/after this date CHR
PEDIGREE= / data source (INFLIGHT,GROUND,MODEL,DUMMY) & date CHR
DESCRIP = / description of reference data CHR
END
[Listing Version 01 6-JUN-1995]
4.1.6 Data Quality Initialization Files (QIN): <unique name>.R5H
The HRS data quality initialization files contain a priori information concerning the effect of the HRS’s diode arrays on the quality of output data values.
Format: Data quality initialization data files contain a single group of data with 512 entries corresponding to the 512 diodes of each HRS detector. Data quality initialization values are stored in REAL*4 format.
Flags and Indicators: The data quality initialization file is selected on the basis of the DETECTOR keyword.
Restrictions: The HRS calibration software will reject any inappropriately sized groups. The following listing shows a sample HRS data quality initialization file.
SIMPLE = F / image conforms to the fits standard L1
BITPIX = 32 / bits per data value I2
ATATYPE= REAL*4 / datatype of the group array CHR
NAXIS = 1 / number of data axes I2
NAXIS1 = 512 / words per group I2
GROUPS = T / image is in group format L1
GCOUNT = 1 / number of groups I2
PCOUNT = 0 / number of group parameters I2
PSIZE = 0 / bits in the group parameter block I2
/ HRS DATA DESCRIPTOR KEYWORDS
INSTRUME= HRS / instrument CHR
FILETYPE= DQ INIT / data quality initialization file CHR
HEADNAME= / reference header file name CHR
DATANAME= / reference data file name CHR
DATE = / date this file was written CHR
/ HRS DATA REDUCTION KEYWORDS
DETECTOR= / detector: 1,2 I2
/ HRS DATA QUALITY KEYWORDS
USEAFTER= / use this file for obs. taken on/after this date CHR
PEDIGREE= / data source (INFLIGHT,GROUND,MODEL,DUMMY) & date CHR
DESCRIP = / description of reference data CHR
END
[Listing Version 01 6-JUN-1995]
4.1.7 SAA Model 7 Contour File (SAA): <unique name>.R6H
The SAA Model 7 contour file contains an image of the SAA Model 7 contour as defined by the HST PDB.
Format: The SAA Model 7 contour file contains a single group of data with dimensions of 360 entries by 180 entries sto red in INTEGER format. The 360 entries represent geographic longitude covering a range of -180 degrees to +180 degrees; the 180 entries represent geographic latitude covering a range of -90 degrees to +90 degrees. The file contains only the values of 0 and 1. The value 0 denotes regions outside of the SAA; 1 denotes regions within the SAA, including the boundary.
Flags and Indicators: Other than the invocation of the background count rate model via the BMD_CORR keyword, there is no selection criterion for this file.
Restrictions: The HRS software will reject any inappropriately sized groups. The following listing shows a sample HRS SAA Model 7 contour file.
GROUPS = T / image is in group format L1
GCOUNT = 1 / number of groups I2
COUNT = 0 / number of group parameters I2
PSIZE = 0 / bits in the group parameter block I2
/ HRS DATA DESCRIPTOR KEYWORDS
INSTRUME= HRS / instrument CHR
FILETYPE= SAA Contour Mask / SAA Contour Mask file CHR
HEADNAME= saahfile.r6H / reference header file name CHR
DATANAME= saahfile.r6d / reference data file name CHR
DATE = 26/11/96 / date this file was written CHR
PEDIGREE= MODEL / source of reference file CHR
ESCRIP = SAA Contour Model 7 from PDB for Model BKGD correction CHR
USEAFTER= 24/04/90 / use file for obs. taken on/after this date CHR
END
4.2 HRS Reference Relations and STSDAS Tables
4.2.1 Line Mapping Parameters Table: <unique name>.CZ1
The line mapping parameters table contains the coefficients of the line mapping function that relates Y-deflection to line position on the photocathode.
Format: Records of line mapping coefficients are organized, for each detector value, by Y- deflection.
Selection Scheme: Data records are selected on the basis of detector. Table 4-1 describes the HRS line mapping parameters table.
Table 4-1. HRS Line Mapping Parameters Table, <unique name>. CZ1
Column Name |
Data Type |
Units |
Description |
|---|---|---|---|
DETECTOR |
I |
D |
line units/deflection units |
YDEF |
I |
– |
Detector number, 1-2 |
L0 |
D |
deflection units line units |
Y-deflection |
ERROR_L0 |
D |
line units |
Zeroth order coefficient of the line mapping function |
A ERROR_A |
D |
line units/deflection units |
Error associated with l0 |
4.2.2 Sample Mapping Parameters Table: <unique name>.CZ2
The sample mapping parameters table contains the coefficients of the sample mapping function that relates Y-deflection and diode position to sample position of the photocathode.
Format: Records of sample mapping coefficients are organized, for each detector value, by Y- deflection. The calibration software interpolates sample mapping coefficients using Y- deflection. Fields are provided for estimates of error in the sample mapping coefficients. These estimates, which are for documentation purposes only, are not used by calibration software.
Selection Scheme: Records are selected on the basis of detector.
Table 4-2 describes the structure of the sample mapping parameters table.
Table 4-2. HRS Sample Mapping Parameters Table, <unique name>. CZ2
Column Name |
Data Type |
Units |
Description |
|---|---|---|---|
DETECTOR |
I |
– |
Detector number, 1-2 |
YDEF |
I |
deflection units |
Y-deflection |
S0 |
D |
sample units |
Zeroth order coefficient of the sample mapping function |
ERROR_S0 |
D |
sample units |
Error associated with s0 |
B |
D |
sample units/deflection units |
First order coefficient of the sample mapping function (dx) |
ERROR_B |
D |
sample units/deflection units |
Error associated with b |
C |
D |
ample units/deflection units2 |
Second order coefficient of the sample mapping function (dx) |
ERROR_C |
D |
sample units/deflection units2 |
Error associated with c |
E |
D |
sample units |
Sample position increment |
ERROR_E |
D |
sample units |
Error associated with e |
4.2.3 Detector Parameters Table: <unique name>.CZ3
The detector parameters table contains the miscellaneous calibration parameters that are functions of detector.
Format: Each set of detector parameters consists of such items as the positions of X and Y null deflections, scale factors for the deflection calibration corrections, diode offsets used to compute effective channel numbers of background diodes, mean and median filter widths and tolerances used to relate bins of data to gross spectra, and corresponding background data.
Selection Scheme: Records are selected on the basis of detector. Table 4-3 describes the structure of the detector parameters table.
Table 4-3. HRS Detector Parameters Table, <unique name>. CZ3 (1 of 2)
Column Name |
Data Type |
Units |
Description |
|---|---|---|---|
DETECTOR |
I |
deflection units |
Position of null deflection in the Y-direction |
DXNULL |
I |
sample units |
Sample position at the center of the photocathode |
DYNULL |
I |
mm/sample |
Conversion factor from sample units to millimeters |
S0 |
D |
units |
Scale factor for the X null deflection component of the deflection |
C |
I |
– |
calibration correction ZXDCAL |
NXSCALE |
I |
– |
Scale factor for the X proportional (plate scale) component of the |
PXSCALE |
I |
diodes |
deflection calibration correction ZXDCALP |
C1 |
I |
diodes |
Diode position offset set used to compute the effective channel number |
C2 |
I |
diodes |
for background diodes to the left of the main diode array |
SKY_MNFWIDTH |
I |
diodes |
Diode position offset set used to compute theeffective channel number |
SKY_MDFWIDTH |
I |
diodes |
for background diodes to the right of the main diode array |
INT_MNFWIDTH |
I |
diodes |
Width of the mean filter used in smoothingbackground data obtained as |
INT_MDFWIDTH |
D |
deflection units |
sky from another aperture (diode number) |
YT0L1 |
D |
deflection units |
Width of the median filter used in smoothingbackground data obtained as |
YT0L2 |
D |
deflection units |
sky from another aperture (diode number) |
YT0L3 |
D |
– |
Width of the mean filter used in smoothingbackground data obtained as |
MIN_DIO |
D |
– |
interorder data (diode number) |
MIN_PHC |
D |
– |
Width of the median filter used in smoothingbackground data obtained as |
MIN_ECH |
D |
– |
interorder data (diode number) |
MIN_ABS |
D |
.125 sec |
Y-deflection tolerance used to determine the binsassociated with a gross |
DELTA_T |
D |
minutes |
spectrum |
PERIOD |
D |
– |
Y-deflection tolerance used to associate a grossspectrum |
AP_RATIO |
I |
– |
with an interorder spectrum |
INT_ORDER |
– |
Detector number, 1-2 |
Y-deflection tolerance used to associate a grossspectrum with the |
I |
deflection units |
Position of null deflection in the X-direction |
specified background diodes of an interorder spectrum |
4.2.4 Wavelength Ranges Table: <unique name>.CZ4
The wavelength ranges table contains the valid wavelength range for each HRS grating and echelle mode.
Format: Each record specifies a range of valid wavelengths associated with a grating and echelle mode.
Selection Scheme: Records are selected based on the grating/echelle mode. Table 4-4 shows the structure of the HRS wavelength ranges table.
Table 4-4. HRS Wavelength Ranges Table, <unique name>. CZ4
Column Name |
Data Type |
Units |
Description |
|---|---|---|---|
GRATING |
CH*9 |
– |
Grating/echelle mode |
LOWER |
D |
Å |
Lower bound of a range of wavelengths |
UPPER |
D |
Å |
Upper bound of a range of wavelengths |
4.2.5 Spectral Order Constants Table: <unique name>.CZ5
The spectral order constants table contains the constants used to determine the spectral order of an HRS observation when an echelle mode is used.
Format: Records of data are indexed by the grating and echelle mode (E-A or E-B) and contain the constants needed to compute the spectral order.
Selection Scheme: Records are selected on the basis of grating/echelle mode. Restrictions: Grating/echelle modes are limited to E-A and E-B.
Table 4-5 describes the structure of the spectral order constants reference table.
Table 4-5. HRS Spectral Order Constants Table, <unique name>. CZ5
Column Name |
Data Type |
Units |
Description |
|---|---|---|---|
GRATING |
CH*9 |
– |
Grating/echelle mode: E-A, E-B |
CAP_A |
D |
Å |
Constant A used to compute the spectral order |
LIT_A |
D |
deflection units |
Constant a used to compute the spectral order |
CAP_B |
D |
encoder units |
Constant B used to compute the spectral order |
LIT_B |
D |
deflection units/ Å |
Constant b used to compute the spectral order |
CAP_C |
D |
encoder units |
Constant C used to compute the spectral order |
LIT_D |
D |
deflection units/ Å |
Constant d used to compute the spectral order |
4.2.6 Dispersion Constants Table: <unique name>.CZ6
The dispersion constants table contains dispersion constants and a corresponding calibration temperature value that are used to generate an HRS wavelength scale.
Format: Records of dispersion constants and the calibration temperature associated with them are stored as a tabular function of grating mode and carrousel position. For the particular grating and echelle mode of the observation, interpolation in the carrousel position is performed during calibration to adjust these constants to the carrousel position of the observation.
Selection Scheme: Records are selected based on the grating/echelle mode. Table 4-6 describes the HRS dispersion constants table.
Table 4-6. HRS Dispersion Constants Table, <unique name>. CZ6 (1 of 2)
Column Name |
Data Type |
Units |
Description |
|---|---|---|---|
GRATING |
CH*9 |
– |
Grating/echelle mode |
CARPOS |
I |
– |
Carrousel position |
ZRIUTA |
D |
deg Celsius |
RIU A temperature |
ZRIUTB |
D |
deg Celsius |
RIU B temperature |
ZDETT1 |
D |
deg Celsius |
Detector 1 temperature |
ZDETT2 |
D |
deg Celsius |
Detector 2 temperature |
ZDEBTF |
D |
deg Celsius |
DEB front post AMPS temperature |
ZDEBTR |
D |
deg Celsius |
DEB rear post AMPS temperature |
ZPABT1 |
D |
deg Celsius |
Detector 1 pre-amp assembly box temperature |
ZPABT2 |
D |
deg Celsius |
Detector 2 pre-amp assembly box temperature |
ZMEBT1 |
D |
deg Celsius |
Main electronic box 1 temperature |
ZMEBT2 |
D |
deg Celsius |
Main electronic box 2 temperature |
ZFIAT |
D |
deg Celsius |
Fixture interface A temperature |
ZFIBT |
D |
deg Celsius |
Fixture interface B temperature |
ZFICT |
D |
deg Celsius |
Fixture interface C temperature |
ZCST |
D |
deg Celsius |
Carrousel stator temperature |
ZCST1 |
D |
deg Celsius |
Detector 1 spectral calibration lamp temperature |
ZCST2 |
D |
deg Celsius |
Detector 2 spectral calibration lamp temperature |
ZHVPST1 |
D |
deg Celsius |
Detector 1 HVPS temperature |
ZHVPST2 |
D |
deg Celsius |
Detector 2 HVPS temperature |
ZDT11 |
D |
deg Celsius |
Detector 1 detector shield temperature |
ZDT12 |
D |
deg Celsius |
Detector 2 detector shield temperature |
ZDRT |
D |
deg Celsius |
Digicon radiator temperature |
ZOBBT |
D |
deg Celsius |
Optical bench bulkhead temperature |
A0 |
D |
sample units |
Dispersion constant |
A1 |
D |
sample units/Å |
Dispersion constant |
A2 |
D |
sample units/Å 2 |
Dispersion constant |
A3 |
D |
sample units |
Dispersion constant |
A4 |
D |
sample units/Å |
Dispersion constant |
A5 |
D |
sample units/Å |
Dispersion constant |
A6 |
D |
sample units/Å 2 |
Dispersion constant |
A7 |
D |
sample units/Å 3 |
Dispersion constant |
4.2.7 Thermal Constants Table: <unique name>.CZ7
The thermal constants table contains the observation temperature mnemonic and the scaling factor for each grating/echelle mode. These data are used in performing a thermal motion correction for the 0th order dispersion constant.
Format: Each record contains an observation temperature mnemonic that also serves as the name of a keyword appearing in the Standard Header Packet (SHP) header files. For a given grating/echelle mode, the calibration code selects the appropriate temperature mnemonic and retrieves the corresponding keyword temperature value from the SHP header factor included in this relation and used to adjust the low-order wavelength coefficient for temperature effects.
Selection Scheme: Records are selected on the basis of the grating/echelle mode. Table 4-7 shows the structure of a thermal constants table.
Table 4-7. HRS Thermal Constants Table, <unique name>. CZ7
Column Name |
Data Type |
Units |
Description |
|---|---|---|---|
GRATING |
CH*9 |
– |
Celsius |
TOBS |
CH*8 |
– |
Grating/echelle mode |
TC |
D |
sample units/deg |
Observation temperature name to be used for thermal correction: ZRIUTA, |
4.2.8 Incidence Angle Constants Table: <unique name>.CZ8
The incidence angle constants table contains the constants needed to perform the incidence angle correction.
Format: The records of this table consist of values for two parameters (a and b) associated with a different grating mode. Each record is also labeled with a carrousel position and order number associated with a grating mode. Interpolation in carrousel position for these constants is carried out when an exact match in this table is not found.
Selection Scheme: Records are selected on the basis of aperture, grating mode, and spectral order.
Restrictions: All possible spectral orders for the echelle modes are expected in this table since interpolation in the spectral order is not performed. Table 4-8 describes the incidence angle constants reference table.
Table 4-8. HRS Incidence Angle Constants Table, <unique name>. CZ8
Column Name |
Data Type |
Units |
Description |
|---|---|---|---|
APERTURE |
CH*3 |
– |
Aperture (SC1, SC2, or LSA) |
GRATING |
CH*9 |
– |
Grating/echelle mode |
CARPOS |
I |
encoder units |
Carrousel position |
SPORDER |
I |
– |
Spectral order associated with constants a and b |
A |
D |
Å |
Constant a |
B |
D |
Å/sample units |
Constant b |
4.2.9 Echelle Interpolation Constants Table: <unique name>.CZ9
The echelle interpolation constants table contains constants used in the echelle ripple correction. Format: Records contain the constants used to compute the normalized grating efficiency that are indexed by spectral order and carrousel position. Interpolation is performed in the carrousel position.
Selection Scheme: Records are retrieved on the basis of grating mode and spectral order.
Restrictions: Records for all possible spectral orders must be present in this table as interpolation in spectral order is not performed.
Table 4-9 describes the structure of the echelle interpolation constants table.
Table 4-9. HRS Echelle Ripple Interpolation Constants Table, <*unique name*>. CZ9
Column Name |
Data Type |
Units |
Description |
|---|---|---|---|
GRATING |
CH*9 |
– G |
rating/echelle mode |
CARPOS |
I |
encoder units |
Carrousel position |
SPORDER |
I |
– |
Spectral order associated with constants a and b |
A |
D |
– |
Constant a |
B |
D |
– |
Constant b |
4.2.10 Echelle Non-interpolation Constants Table: < unique name>.CZA
The echelle non-interpolation constants table contains constants used in the echelle ripple correction. These constants are not interpolated.
Format: Each record contains those constants used to compute the normalized grating efficiency that rely solely upon the grating/echelle mode.
Selection Scheme: Records are retrieved based on the grating/echelle mode. Table 4-10 describes the structure of the echelle non-interpolation constants table.
Table 4-10. HRS Echelle Non-interpolation Constants Table, <unique name>. CZA
Column Name |
Data Type |
Units |
Description |
|---|---|---|---|
GRATING |
CH*9 |
– |
Grating/echelle mode |
F |
D |
mm |
Focal length |
BETA |
D |
deg |
Echelle blaze angle |
DELTA |
D |
deg |
Half-angle between collimator and cross-disperser |
CPNORM |
I |
encoder units |
Echelle center carrousel position |
RO |
I |
encoder units C |
onstant used in the computation of angle THETA |
4.2.11 Scattered Light Coefficients Table: < unique name>.CZB
The scattered light coefficients table contains the coefficients for determining the contribution of scattered light to the background.
Format: Records contain four scattered light coefficients and are organized by aperture, grating/echelle mode, and spectral order. The four coefficients a_scat, b_scat, c_scat, and d_scat are used in the following equation to determine the background spectrum:
math:
B(i) = 0:5 * [a_{scat} * U(i) + b_{scat} \* L(i)] - c_{scat} \* N(i) + d_{scat} \* N
where
N(i) = O(i) - 0.5 \* [U(i) + L(i)] B(i) is the background spectrum
U(i) is the upper interorder count rate per diode
L(i) is the lower interorder count rate per diode
N(i) is the net on-order count rate per diode
O(i) is the gross object spectrum count rate per diode
N is the average net on-order count rate per diode averaged over all science diodes
i is the science diode light subtraction index
Selection Scheme: Records are selected on the basis of aperture, grating/echelle mode, and spectral order.
Table 4-11 shows the structure of the HRS scattered light coefficients table.
Table 4-11. HRS Scattered Light Subtraction Coefficients Table, <unique name>.CZB
Column Name |
Data Type |
Units |
Description |
|---|---|---|---|
APERTURE |
CH*3 |
– |
Aperture (LSA or SSA) |
RATING |
CH*9 |
– |
Grating/echelle mode |
SPORDER |
I |
– |
Spectral order |
A_SCAT |
R |
– |
Scattered light coefficient a |
B_SCAT |
R |
– |
Scattered light coefficient b |
C_SCAT |
R |
– |
Scattered light coefficient c |
D_SCAT |
R |
– |
Scattered light coefficient d |
4.2.12 Global Wavelength Coefficients Table: < unique name>.CZC
The global wavelength coefficients table contains the values for the global coefficients solution to determining the wavelength scale of an observation. The coefficients for temperature and time correction factors to the wavelength scale, based on the global coefficient solution, are also included.
Format: Records of global coefficient, temperature, and time constants are indexed by grating mode. Each record contains the necessary information to determine the dispersion coefficients used to calculate the wavelength solution for a given observation.
Selection Scheme: Records are selected on the basis of grating mode.
Table 4-12 shows the structure of the HRS global wavelength coefficients table.
Table 4-12. HRS Global Wavelength Coefficients Table,<unique name>. CZC
Column Name |
Data Type |
Units |
Description |
|---|---|---|---|
GRATING |
CH*9 |
– |
Grating/echelle mode |
MCENTER |
I |
– |
Central order of the grating |
F00 |
D |
sample units |
Global coefficient |
F01 |
D |
sample units |
Global coefficient |
F02 |
D |
sample units |
Global coefficient |
F10 |
D |
(sample units)/ Å |
Global coefficient |
F11 |
D |
(sample units)/ Å/(encoder units) |
Global coefficient |
F12 |
D |
(sample units)/ Å/(encoder units)2 |
Global coefficient |
F20 |
D |
(sample units)/ Å2 |
Global coefficient |
F21 |
D |
(sample units)/ Å2/(encoder units) |
Global coefficient |
F22 |
D |
(sample units)/ Å2/(encoder units) 2 |
Global coefficient |
F40 |
D |
(sample units)/ Å |
Global coefficient |
F41 |
D |
(sample units)/ Å/(encoder units) |
Global coefficient |
F42 |
D |
(sample units)/ Å/(encoder units)2 |
Global coefficient |
F50 |
D |
(sample units)/ Å |
Global coefficient |
F51 |
D |
(sample units)/ Å/(encoder units) |
Global coefficient |
F52 |
D |
(sample units)/ Å/(encoder units)2 |
Global coefficient |
ZRIUTA |
D |
deg Celsius |
RIU a temperature |
ZRIUTB |
D |
deg Celsius |
RIU b temperature |
ZDETT1 |
D |
deg Celsius |
Detector 1 temperature |
ZDETT2 |
D |
deg Celsius |
Detector 2 temperature |
ZDEBTF |
D |
deg Celsius |
DEB front post amps temperature |
ZDEBTR |
D |
deg Celsius |
DEB rear post amps temperature |
ZPABT1 |
D |
deg Celsius |
Detector 2 pre-amp assembly box temperature |
ZMEBT1 |
D |
deg Celsius |
Main electronic box 1 temperature |
ZMEBT2 |
D |
deg Celsius |
Fixture interface a temperature |
ZFIBT |
D |
deg Celsius |
Fixture interface b temperature |
ZFICT |
D |
deg Celsius |
Fixture interface c temperature |
ZCST |
D |
deg Celsius |
Carrousel stator temperature |
ZSCT1 |
D |
deg Celsius |
Detector 1 spectral cal-lamp temperature |
ZSCT2 |
D |
deg Celsius |
Detector 2 spectral cal-lamp temperature |
ZHVPST1 |
D |
deg Celsius |
Detector 1 HVPS temperature |
ZHVPST2 |
D |
deg Celsius |
Detector 2 HVPS temperature |
ZDT11 |
D |
deg Celsius |
Detector 1 detector shield temperature |
ZDT12 |
D |
deg Celsius |
Detector 2 detector shield temperature |
ZDRT |
D |
deg Celsius |
Digicon radiator temperature |
ZOBBT |
D |
deg Celsius |
Optical bench bulkhead temperature |
4.2.13 Photocathode Blemish Location Table: < unique name>.CZD
The photocathode blemish location table contains the locations of known blemishes in each of the HRS detectors caused by scratches, pits, and other microscopic imperfections in the detector window and photocathode.
Format: Each entry defines the location of one blemish. Blemishes are defined by a rectangle region bordered by the lower and upper line position and smaller to larger sample position. The data quality flag that should be assigned to the calibrated spectra by calhrs is found in the column EPSILON.
Selection Scheme: Records are selected based on the detector used and the line and sample position of the observed spectrum.
Table 4-13 shows the structure of the HRS photocathode blemish location table.
Table 4-13. HRS Photocathode Blemish Locations Table, <unique name>. CZD
Column Name |
Data Type |
Units |
Description |
|---|---|---|---|
DETECTOR |
I |
– |
Detector number |
LINE1 |
D |
line units |
Starting lower line position of the blemish |
LINE2 |
D |
line units |
Ending upper line position of the blemish |
SAMPLE1 |
D |
sample units |
Starting lower sample position of the blemish |
SAMPLE2 |
D |
sample units |
Ending upper sample position of the blemish |
EPSILON |
I |
– |
Data quality flag associated with the blemish |
DEPTH |
D |
% |
Maximum depth of blemish |
4.2.14 HRS Background Count Rates Table: <unique name>.CZE
The FOS BLUE detector predicted mean background count rates are stored as a function of geomagnetic latitude and longitude. The header keywords, D1SCALE and D2SCALE, are multiplicative scale factors used to adjust the background count rate model to the appropriate HRS detector. D1SCALE adjusts to the HRS Side 1; D2SCALE adjusts to the HRS Side 2. The mean background count rate at the time and position of the observation is interpolated from this table and used as the background spectrum during calibration.
Format: Records of background count rates are organized by detector, geomagnetic latitude, and geomagnetic longitude.
Selection Scheme: All records and the header keywords that represent scaling factors are selected.
Table 4-14 shows the structure of the background count rates table, < unique name>.CZE, as a function of geomagnetic position.
Table 4-14. HRS Background Count Rates Table, <unique name>. CZE
Column Name |
Data Type |
Units |
Description |
|---|---|---|---|
FOS_DETECTOR |
BACK_RATE |
I*8 |
count/s |
BLUE |
CH*4 |
– |
Reference FOS detector: |
GM_LAT |
I*4 |
degrees |
Geomagnetic latitude |
GM_LONG |
I*4 |
degrees |
Geomagnetic longitude |
The scaling factor header keywords are D1SCALE and D2SCALE.