Reference File Conventions

Supported CRDS file formats

FITS

ASDF

JSON

YAML

Required Keywords and Properties

Reference files specify metadata as keyword values that CRDS often checks. In general, instrument configuration parameters can be used to automatically add reference files to CRDS rmaps which describe how to assign them. In essence, each reference file is required to specify the instrument configurations for which it is the best reference file. CRDS supports the use of patterns and/or substitutions for keyword values which enable as single reference file to support more than one instrument configuration.

Keywords For New File Formats

Newer file formats used for JWST and Roman such as ASDF and JSON have equivalent “keywords” that are generally organized hierarchically in a reference’s metadata tree.

For JWST, the calibration code defines file format schema which show the correspondence between “data model path” and more primitive representations like FITS keywords: Data Models Schema.

The schema also describe related facts such as parameter type and valid values. For instance, the model path:

META.INSTRUMENT.DETECTOR

is equivalent to the FITS keyword:

DETECTOR

while:

META.INSTRUMENT.NAME

corresponds to the FITS keyword:

INSTRUME

To isolate CRDS from physical file formats for JWST, CRDS generally uses datamodel paths to refer to metadata; by convention CRDS converts them to all uppercase.

For ASDF, the equivalent metadata might be hierarchically encoded as:

meta:
    instrument:
        detector: NRS1
        name: NIRSPEC

In this case, the keyword DETECTOR does not exist at all in ASDF, but the model path still does.

Roman calibration code defines the file format schema of asdf files via Roman Datamodels. To isolate CRDS from physical file formats for Roman, CRDS generally uses datamodel paths to refer to metadata; by convention CRDS converts them to all uppercase. For example, the file metadata might be hierarchically encoded as

roman:
    meta:
        instrument:
            detector: WFI01
            name: WFI

For CRDS, this is equivalent to:

'ROMAN.META.INSTRUMENT.NAME': 'WFI'
'ROMAN.META.INSTRUMENT.DETECTOR': 'WFI01'

Boilerplate Keywords

Each mission defines a small set of required keywords for reference file provenance information:

Boiler Plate Keywords
FITS	VALUES
TELESCOP	HST
INSTRUME	ACS
FILETYPE	BIAS
USEAFTER	2017-10-01T00:00:00
PEDIGREE	DUMMY, GROUND, IN FLIGHT
HISTORY	File creation notes
COMMENT	Additional notes
DESCRIP	Brief description

Boiler Plate Keywords
FITS	DATAMODELS	VALUES
TELESCOP	META.TELESCOPE	JWST
INSTRUME	META.INSTRUMENT.NAME	MIRI
REFTYPE	META.REFERENCE.TYPE	DARK
USEAFTER	META.USEAFTER	2017-10-01T00:00:00
AUTHOR	META.AUTHOR	Homer Simpson
PEDIGREE	META.PEDIGREE	DUMMY, GROUND, IN FLIGHT
HISTORY	META.HISTORY	File creation notes
DESCRIP	META.DESCRIPTION	Brief description

Boiler Plate Keywords
ROMAN_DATAMODELS	VALUES
ROMAN.META.TELESCOPE	ROMAN
ROMAN.META.INSTRUMENT.NAME	WFI
ROMAN.META.REFERENCE.TYPE	DARK
ROMAN.META.USEAFTER	2017-10-01T00:00:00
ROMAN.META.AUTHOR	Homer Simpson
ROMAN.META.PEDIGREE	DUMMY, GROUND, IN FLIGHT
ROMAN.META.HISTORY	File creation notes
ROMAN.META.DESCRIPTION	Brief description

Matching Keyword Patterns

To support automatic rmap updates, any keyword used to assign best references must be added to the reference metadata. For example, if a FITS reference type uses DETECTOR to help assign a reference in the rmap, the reference file is required to define DETECTOR or P_DETECT.

Discrete/Real Values

Very often the applicability of a reference file can be defined by a single discrete real world value, or by a simple one word wild card such as ANY or N/A:

META.INSTRUMENT.DETECTOR = NRS1

Where applicable, a discrete valued keyword will describe the instrument configuration used to create the reference file.

Conditional Pattern Substitutions

Sometimes it is useful to apply one reference file to a number of specific real world keyword values, i.e. some limited set of readout patterns, not merely the single valued instrument configuration used to obtain the reference data.

HST used hidden substitution rules built into CDBS and CRDS to describe patterns of values not suitable for FITS keywords:

{'acs': {
    'APERTURE': {
        "DETECTOR=='WFC' and APERTURE=='ANY_FULL' and DATE_OBS < '2016-09-25'": 'NONE|WFC|WFC-FIX|WFC1|WFC1-CTE|WFC1-FIX|WFC1-IRAMP|WFC1-MRAMP|WFC2|WFC2-FIX|WFC2-MRAMP|WFC2-ORAMP|WFCENTER|WFC1A-512|WFC1B-512|WFC2C-512|WFC2D-512|WFC1A-1K|WFC1B-1K|WFC2C-1K|WFC2D-1K|WFC1A-2K|WFC1B-2K|WFC2C-2K|WFC2D-2K',
        "DETECTOR=='WFC' and APERTURE=='ANY_FULL' and DATE_OBS >= '2016-09-25'": 'NONE|WFC|WFC-FIX|WFC1|WFC1-CTE|WFC1-FIX|WFC1-IRAMP|WFC1-MRAMP|WFC2|WFC2-FIX|WFC2-MRAMP|WFC2-ORAMP|WFCENTER|WFC1A-512|WFC1B-512|WFC2C-512|WFC2D-512|WFC1A-1K|WFC1B-1K|WFC2C-1K|WFC2D-1K|WFC1A-2K|WFC1B-2K|WFC2C-2K|WFC2D-2K|WFC1-POL0V|WFC1-POL60V|WFC1-POL120V|WFC1-POL0UV|WFC1-POL60UV|WFC1-POL120UV|WFC1-IRAMPQ|WFC1-MRAMPQ|WFC2-MRAMPQ|WFC2-ORAMPQ|WFC1-SMFL|WFC2-SMFL',
        "DETECTOR=='WFC' and APERTURE=='ANY_WFC1_2K' and DATE_OBS < '2016-09-25'": 'WFC1-2K|WFC1-POL0UV|WFC1-POL0V|WFC1-POL120UV|WFC1-POL120V|WFC1-POL60UV|WFC1-POL60V|WFC1-IRAMPQ|WFC1-MRAMPQ|WFC1-SMFL',
        "DETECTOR=='WFC' and APERTURE=='ANY_WFC1_2K' and DATE_OBS >= '2016-09-25'": 'WFC1-2K',
        "DETECTOR=='WFC' and APERTURE=='ANY_WFC2_2K' and DATE_OBS < '2016-09-25'": 'WFC2-2K|WFC2-POL0UV|WFC2-POL0V|WFC2-POL120UV|WFC2-POL120V|WFC2-POL60UV|WFC2-POL60V|WFC2-MRAMPQ|WFC2-ORAMPQ|WFC2-SMFL',
        "DETECTOR=='WFC' and APERTURE=='ANY_WFC2_2K' and DATE_OBS >= '2016-09-25'": 'WFC2-2K',
    },
    'CCDAMP': {
        "DETECTOR=='HRC' and CCDAMP=='ANY'": 'A|ABCD|AD|B|BC|C|D',
        "DETECTOR=='WFC' and CCDAMP=='ABCDALL'": 'A|ABCD|B|C|D',
        "DETECTOR=='WFC' and CCDAMP=='ANY'": 'A|ABCD|AD|B|BC|C|D',
    },
    'CCDGAIN': {
        "DETECTOR=='HRC' and CCDGAIN=='-1'": '1.0|2.0|4.0|8.0',
        "DETECTOR=='WFC' and CCDGAIN=='-1'": '0.5|1.0|1.4|2.0',
        "DETECTOR in ['WFC', 'HRC'] and CCDGAIN=='-999'": '1.0|2.0|4.0|8.0',
        "DETECTOR in ['WFC', 'HRC'] and CCDGAIN=='-999.0'": '1.0|2.0|4.0|8.0',
    },
    'FILTER1': {
        "DETECTOR=='HRC' and FILTER1=='ANY'": 'CLEAR1S|F475W|F502N|F550M|F555W|F606W|F625W|F658N|F658N|F775W|F850LP|F892N|G800L|POL0UV|POL120UV|POL60UV',
        "DETECTOR=='SBC' and FILTER1=='ANY' and OBSTYPE=='IMAGING'": 'BLOCK1|BLOCK2|BLOCK3|BLOCK4|F115LP|F122M|F125LP|F140LP|F150LP|F165LP',
        "DETECTOR=='SBC' and FILTER1=='ANY' and OBSTYPE=='SPECTROSCOPIC'": 'PR110L|PR130L',
        "DETECTOR=='WFC' and FILTER1=='ANY'": 'CLEAR1L|F475W|F502N|F550M|F555W|F606W|F625W|F658N|F775W|F850LP|F892N|G800L|POL0UV|POL120UV|POL60UV'
    },
    'FILTER2': {
        "DETECTOR=='HRC' and FILTER2=='ANY'": 'CLEAR2L|CLEAR2S|F220W|F250W|F330W|F344N|F435W|F660N|F814W|FR388N|FR459M|FR505N|FR656N|FR914M|POL0V|POL120V|POL60V|PR200L',
        "DETECTOR=='WFC' and FILTER2=='ANY'": 'CLEAR2L|F330W|F435W|F660N|F814W|FR1016N|FR388N|FR423N|FR459M|FR462N|FR505N|FR551N|FR601N|FR647M|FR656N|FR716N|FR782N|FR853N|FR914M|FR931N|POL0V|POL120V|POL60V'
    },
    'FLASHCUR': {"FLASHCUR=='ANY'": 'HIGH|LOW|MED'},
    'LRFWAVE' : {
        "LRFWAVE == '3774.0'" : 'between 3710 3826',
        "LRFWAVE == '3880.0'" : 'between 3826 3936',
        "LRFWAVE == '3992.0'" : 'between 3936 4051',
        "LRFWAVE == '4105.0'" : 'between 4051 4167',
        "LRFWAVE == '4230.0'" : 'between 4167 4296',
        "LRFWAVE == '4362.0'" : 'between 4296 4421',
        "LRFWAVE == '4488.0'" : 'between 4421 4554',
        "LRFWAVE == '4620.0'" : 'between 4554 4686',
        "LRFWAVE == '4752.0'" : 'between 4686 4821',
        "LRFWAVE == '5038.0'" : 'between 4821 5271',
        "LRFWAVE == '5491.0'" : 'between 5271 5751',
        "LRFWAVE == '5998.0'" : 'between 5751 6271',
        "LRFWAVE == '6505.0'" : 'between 6271 6851',
        "LRFWAVE == '7205.0'" : 'between 6851 7471',
        "LRFWAVE == '7836.0'" : 'between 7471 8161',
    },
  'OBSTYPE': {
      "DETECTOR=='HRC' and FILTER1=='G800L' and OBSTYPE=='ANY'": 'CORONAGRAPHIC|IMAGING'
  },
  'NAXIS1': {"DETECTOR=='WFC' and APERTURE=='ANY_FULL'": 'ANY',},
  'NAXIS2': {"DETECTOR=='WFC' and APERTURE=='ANY_FULL'": 'ANY',},
  'LTV1': {"DETECTOR=='WFC' and APERTURE=='ANY_FULL'": 'ANY',},
  'LTV2': {"DETECTOR=='WFC' and APERTURE=='ANY_FULL'": 'ANY',},
  'SHUTRPOS': {"SHUTRPOS=='ANY'": 'A|B'},
},
'cos': {
    'LIFE_ADJ': {
        "LIFE_ADJ=='-11'": '-1.0|1.0',
        "LIFE_ADJ=='-11.0'": '-1.0|1.0'
    },
    'OPT_ELEM': {
        "DETECTOR=='FUV' and OPT_ELEM=='ANY'": 'G130M|G140L|G160M',
        "DETECTOR=='NUV' and OPT_ELEM=='ANY'": 'G185M|G225M|G230L|G285M|MIRRORA|MIRRORB'
    }
},
'stis': {
    'APERTURE': {
        "OBSTYPE=='IMAGING' and OPT_ELEM=='MIRCUV' and APERTURE=='ANY'": '25MAMA|2X2|6X6|F25NDQ1|F25NDQ2|F25NDQ3|F25NDQ4',
        "OBSTYPE=='IMAGING' and OPT_ELEM=='MIRFUV' and APERTURE=='ANY'": 'F25LYA|F25ND3|F25ND5|F25NDQ|F25NDQ1|F25NDQ2|F25NDQ3|F25NDQ4|F25QTZ|F25SRF2',
        "OBSTYPE=='IMAGING' and OPT_ELEM=='MIRNUV' and APERTURE=='ANY'": '25MAMA|2X2|6X6|F25CIII|F25CN182|F25CN270|F25MGII|F25ND3|F25ND5|F25NDQ|F25NDQ1|F25NDQ2|F25NDQ3|F25NDQ4|F25QTZ|F25SRF2',
        "OBSTYPE=='IMAGING' and OPT_ELEM=='MIRVIS' and APERTURE=='ANY'": '0.05X29|0.05X31NDA|0.05X31NDB|0.09X29|0.1X0.03|0.1X0.06|0.1X0.09|0.1X0.2|0.2X0.05ND|0.2X0.06|0.2X0.06FPA|0.2X0.06FPB|0.2X0.06FPC|0.2X0.06FPD|0.2X0.06FPE|0.2X0.09|0.2X0.2|0.2X0.2FPA|0.2X0.2FPB|0.2X0.2FPC|0.2X0.2FPD|0.2X0.2FPE|0.2X0.5|0.2X29|0.3X0.05ND|0.3X0.06|0.3X0.09|0.3X0.2|0.5X0.5|1X0.06|1X0.2|25MAMA|2X2|31X0.05NDA|31X0.05NDB|31X0.05NDC|36X0.05N45|36X0.05P45|36X0.6N45|36X0.6P45|50CCD|50CORON|52X0.05|52X0.05F1|52X0.05F2|52X0.1|52X0.1B0.5|52X0.1B1.0|52X0.1B3.0|52X0.1F1|52X0.1F2|52X0.2|52X0.2F1|52X0.2F2|52X0.5|52X0.5F1|52X0.5F2|52X2|52X2F1|52X2F2|6X0.06|6X0.2|6X0.5|6X6|F25CIII|F25CN182|F25CN270|F25LYA|F25MGII|F25ND3|F25ND5|F25NDQ|F25NDQ1|F25NDQ2|F25NDQ3|F25NDQ4|F25QTZ|F25SRF2|F28X50LP|F28X50OII|F28X50OIII'
    },
    'CCDAMP': {"CCDAMP=='ANY'": 'A|B|C|D'},
    'CCDGAIN': {"CCDGAIN=='-1'": '1.0|2.0|4.0|8.0'},
    'CENWAVE': {
        "OBSTYPE=='SPECTROSCOPIC' and OPT_ELEM=='E140H' and CENWAVE=='-1'": '1234.0|1271.0|1307.0|1343.0|1380.0|1416.0|1453.0|1489.0|1526.0|1562.0|1598.0',
        "OBSTYPE=='SPECTROSCOPIC' and OPT_ELEM=='E140M' and CENWAVE=='-1'": '1425.0',
        "OBSTYPE=='SPECTROSCOPIC' and OPT_ELEM=='E230H' and CENWAVE=='-1'": '1763.0|1813.0|1863.0|1913.0|1963.0|2013.0|2063.0|2113.0|2163.0|2213.0|2263.0|2313.0|2363.0|2413.0|2463.0|2513.0|2563.0|2613.0|2663.0|2713.0|2762.0|2812.0|2862.0|2912.0|2962.0|3012.0',
        "OBSTYPE=='SPECTROSCOPIC' and OPT_ELEM=='E230M' and CENWAVE=='-1'": '1978.0|2124.0|2269.0|2415.0|2561.0|2707.0',
        "OBSTYPE=='SPECTROSCOPIC' and OPT_ELEM=='G140L' and CENWAVE=='-1'": '1425.0|1575.0',
        "OBSTYPE=='SPECTROSCOPIC' and OPT_ELEM=='G140M' and CENWAVE=='-1'": '1173.0|1218.0|1222.0|1272.0|1321.0|1371.0|1387.0|1400.0|1420.0|1470.0|1518.0|1540.0|1550.0|1567.0|1616.0|1640.0|1665.0|1714.0',
        "OBSTYPE=='SPECTROSCOPIC' and OPT_ELEM=='G230L' and CENWAVE=='-1'": '2376.0',
        "OBSTYPE=='SPECTROSCOPIC' and OPT_ELEM=='G230LB' and CENWAVE=='-1'": '2375.0',
        "OBSTYPE=='SPECTROSCOPIC' and OPT_ELEM=='G230M' and CENWAVE=='-1'": '1687.0|1769.0|1851.0|1884.0|1933.0|2014.0|2095.0|2176.0|2257.0|2338.0|2419.0|2499.0|2579.0|2600.0|2659.0|2739.0|2800.0|2818.0|2828.0|2898.0|2977.0|3055.0',
        "OBSTYPE=='SPECTROSCOPIC' and OPT_ELEM=='G230MB' and CENWAVE=='-1'": '1713.0|1854.0|1995.0|2135.0|2276.0|2416.0|2557.0|2697.0|2794.0|2836.0|2976.0|3115.0',
        "OBSTYPE=='SPECTROSCOPIC' and OPT_ELEM=='G430L' and CENWAVE=='-1'": '4300.0',
        "OBSTYPE=='SPECTROSCOPIC' and OPT_ELEM=='G430M' and CENWAVE=='-1'": '3165.0|3305.0|3423.0|3680.0|3843.0|3936.0|4194.0|4451.0|4706.0|4781.0|4961.0|5093.0|5216.0|5471.0',
        "OBSTYPE=='SPECTROSCOPIC' and OPT_ELEM=='G750L' and CENWAVE=='-1'": '7751.0|8975.0',
        "OBSTYPE=='SPECTROSCOPIC' and OPT_ELEM=='G750M' and CENWAVE=='-1'": '10363.0|5734.0|6094.0|6252.0|6581.0|6768.0|7283.0|7795.0|8311.0|8561.0|8825.0|9286.0|9336.0|9806.0|9851.0',
        "OBSTYPE=='SPECTROSCOPIC' and OPT_ELEM=='PRISM' and CENWAVE=='-1'": '1200.0|2125.0',
        "OBSTYPE=='SPECTROSCOPIC' and OPT_ELEM=='X140H' and CENWAVE=='-1'": '1232.0|1269.0|1305.0|1341.0|1378.0|1414.0|1451.0|1487.0|1523.0|1560.0|1587.0',
        "OBSTYPE=='SPECTROSCOPIC' and OPT_ELEM=='X140M' and CENWAVE=='-1'": '1425.0',
        "OBSTYPE=='SPECTROSCOPIC' and OPT_ELEM=='X230H' and CENWAVE=='-1'": '1760.0|1810.0|1860.0|1910.0|1960.0|2010.0|2060.0|2110.0|2160.0|2210.0|2261.0|2310.0|2360.0|2410.0|2460.0|2511.0|2560.0|2610.0|2660.0|2710.0|2760.0|2810.0|2860.0|2910.0|2960.0|3010.0',
        "OBSTYPE=='SPECTROSCOPIC' and OPT_ELEM=='X230M' and CENWAVE=='-1'": '1975.0|2122.0|2268.0|2414.0|2560.0|2703.0'
    },
    'DETECTOR': {"DETECTOR=='ANY'": 'CCD|FUV-MAMA|NUV-MAMA'},
    'OBSTYPE': {"OBSTYPE=='ANY'": 'IMAGING|SPECTROSCOPIC'},
    'OPT_ELEM': {
        "OBSTYPE=='IMAGING' and OPT_ELEM=='ANY'": 'MIRCUV|MIRFUV|MIRNUV|MIRVIS',
        "OBSTYPE=='SPECTROSCOPIC' and OPT_ELEM=='ANY'": 'E140H|E140M|E230H|E230M|G140L|G140M|G230L|G230LB|G230M|G230MB|G430L|G430M|G750L|G750M|PRISM|X140H|X140M|X230H|X230M'
    }
},
'wfc3': {
    'APERTURE': {
        "DETECTOR=='UVIS' and BINAXIS1=='1' and BINAXIS2=='1' and APERTURE=='CHIP1_SUB_NOCORNERS'": 'UVIS1-2K4-SUB|UVIS1-M512-SUB',
        "DETECTOR=='UVIS' and BINAXIS1=='1' and BINAXIS2=='1' and APERTURE=='CHIP2_SUB_NOCORNERS'": 'UVIS2-2K4-SUB|UVIS2-M512-SUB',
        "DETECTOR=='UVIS' and BINAXIS1=='1' and BINAXIS2=='1' and APERTURE=='CUSTOM_SUBARRAYS'": 'G280-REF|UVIS|UVIS-CENTER|UVIS-FIX|UVIS-QUAD|UVIS-QUAD-FIX|UVIS1|UVIS1-FIX|UVIS2|UVIS2-FIX',
        "DETECTOR=='UVIS' and BINAXIS1=='1' and BINAXIS2=='1' and APERTURE=='FULLFRAME_2AMP'": 'UVIS|UVIS-CENTER|UVIS-FIX|UVIS1|UVIS1-FIX|UVIS2|UVIS2-FIX',
        "DETECTOR=='UVIS' and BINAXIS1=='1' and BINAXIS2=='1' and APERTURE=='FULLFRAME_4AMP'": 'G280-REF|UVIS|UVIS-CENTER|UVIS-FIX|UVIS-IR-FIX|UVIS-QUAD|UVIS-QUAD-FIX|UVIS1|UVIS1-FIX|UVIS2|UVIS2-FIX|UVIS2-C512C-CTE|UVIS2-C1K1C-CTE',
        "DETECTOR=='UVIS' and BINAXIS1=='1' and BINAXIS2=='1' and APERTURE=='QUAD_CORNER_SUBARRAYS'": 'UVIS-QUAD-SUB|UVIS1-2K2A-SUB|UVIS1-2K2B-SUB|UVIS1-C512A-SUB|UVIS1-C512B-SUB|UVIS2-2K2C-SUB|UVIS2-2K2D-SUB|UVIS2-C1K1C-SUB|UVIS2-C512C-SUB|UVIS2-C512D-SUB|UVIS2-M1K1C-SUB|UVIS2-M512C-SUB',
        "DETECTOR=='UVIS' and BINAXIS1=='2' and BINAXIS2=='2' and APERTURE=='ANY'": 'G280-REF|UVIS|UVIS-CENTER|UVIS-FIX|UVIS-IR-FIX|UVIS-QUAD|UVIS-QUAD-FIX|UVIS1|UVIS1-FIX|UVIS2|UVIS2-FIX',
        "DETECTOR=='UVIS' and BINAXIS1=='3' and BINAXIS2=='3' and APERTURE=='ANY'": 'G280-REF|UVIS|UVIS-CENTER|UVIS-FIX|UVIS-IR-FIX|UVIS-QUAD|UVIS-QUAD-FIX|UVIS1|UVIS1-FIX|UVIS2|UVIS2-FIX'
    },
    'CCDAMP': {
        "CCDAMP=='ANY'": 'A|ABCD|AC|AD|B|BC|BD|C|D',
        "CCDAMP=='SINGLE_AMP'": 'A|B|C|D'
    },
    'CCDGAIN': {
        "DETECTOR=='IR' and CCDGAIN=='-1'": '2.0|2.5|3.0|4.0',
        "DETECTOR=='IR' and CCDGAIN=='-1.'": '2.0|2.5|3.0|4.0',
        "DETECTOR=='UVIS' and CCDGAIN=='-1'": '1.0|1.5|2.0|4.0',
        "DETECTOR=='UVIS' and CCDGAIN=='-1.'": '1.0|1.5|2.0|4.0'
    },
    'CHINJECT': {"CHINJECT=='ANY'": 'CONT|LINE10|LINE17|LINE25|NONE'},
    'FILTER': {
        "DETECTOR=='IR' and FILTER=='ANY'": 'BLANK|F093W|F098M|F105W|F110W|F125W|F126N|F127M|F128N|F130N|F132N|F139M|F140W|F153M|F160W|F164N|F167N',
        "DETECTOR=='UVIS' and FILTER=='ANY'": 'CLEAR|F200LP|F218W|F225W|F275W|F280N|F300X|F336W|F343N|F350LP|F373N|F390M|F390W|F395N|F410M|F438W|F467M|F469N|F475W|F475X|F487N|F502N|F547M|F555W|F588N|F600LP|F606W|F621M|F625W|F631N|F645N|F656N|F657N|F658N|F665N|F673N|F680N|F689M|F763M|F775W|F814W|F845M|F850LP|F953N|FQ232N|FQ243N|FQ378N|FQ387N|FQ422M|FQ436N|FQ437N|FQ492N|FQ508N|FQ575N|FQ619N|FQ634N|FQ672N|FQ674N|FQ727N|FQ750N|FQ889N|FQ906N|FQ924N|FQ937N'
    },
    'SAMP_SEQ': {
        "SAMP_SEQ=='ANY'": 'MIF1200|MIF1500|MIF600|MIF900|NONE|RAPID|SPARS10|SPARS100|SPARS200|SPARS25|SPARS350|SPARS50|STEP100|STEP200|STEP25|STEP400|STEP50|UNKNOWN'
    }
  }
}

The HST substition patterns above are of the form:

<instrument>
    <keyword>
      <condition1> : <substitution1>
      <condition2> : <substitution2>
      ...

For each rmap update for instrument, for each matching keyword, each condition is evaluated with respect to the reference file header. If the condition is True then the corresponding substitution is used to replace the value of keyword for the purposes of updating the rmap.

JWST uses a more explicit approach where patterns are specified directly via reference metadata. The CAL code data models define optional keywords beginning with P_ that can have or-ed values. For instance, in FITS parlance:

P_DETECT = NRCA1 | NRCA4 |

means that the reference file should be used for both DETECTOR=NRCA1 and DETECTOR=NRCA4. Typically the P_ keyword name is truncated to the FITS 8 character limit as needed.

The trailing | is required to satisfy the calibration code data model schema checks of allowed patterns.

If no pattern keyword is defined, CRDS will use the equivalent normal keyword specified to update the matching rules. In terms of datamodels paths, the above value would be specified similarly:

META.INSTRUMENT.P_DETECTOR = NRCA1 | NRCA4 |

The following table defines the pattern keywords currently supported for JWST:

JWST Pattern Keyword Names
FITS	`P_` FITS	`P_` DATAMODELS
EXP_TYPE	P_EXP_TY	META.EXPOSURE.P_EXPTYPE
BAND	P_BAND	META.INSTRUMENT.P_BAND
DETECTOR	P_DETECT	META.INSTRUMENT.P_DETECTOR
CHANNEL	P_CHANNE	META.INSTRUMENT.P_CHANNEL
FILTER	P_FILTER	META.INSTRUMENT.P_FILTER
GRATING	P_GRATIN	META.INSTRUMENT.P_GRATING
PUPIL	P_PUPIL	META.INSTRUMENT.P_PUPIL
MODULE	P_MODULE	META.INSTRUMENT.MODULE
SUBARRAY	P_SUBARR	META.SUBARRAY.P_SUBARRAY
READPATT	P_READPA	META.EXPOSURE.P_READPATT

Each P_ keyword is explicitly defined in CRDS code as well as the CAL code data models. Relative to HST substitutions, the advantage of the JWST P_ keywords is that the pattern values can be defined in arbitrary combinations in the reference files instead of CRDS code.

Roman uses the more explicit approach where patterns are specified directly via reference metadata. Roman datamodels code defines optional keywords beginning with P_ that can have or-ed values. For instance, in ASDF parlance:

P_OPTICAL_ELEMENT = F213 | F158 |

means that the reference file should be used for both OPTICAL_ELEMENT=F213 and OPTICAL_ELEMENT=F158.

The trailing | is required to satisfy the calibration code data model schema checks of allowed patterns.

If no pattern keyword is defined, CRDS will use the equivalent normal keyword specified to update the matching rules. In terms of datamodels paths, the above value would be specified similarly:

roman.meta.instrument.p_optical_element = F213 | F158 |

The following table defines the pattern keywords currently supported for Roman:

Roman Pattern Keyword Names
CRDS	`P_` ASDF	`P_` ROMAN DATAMODELS
OPTICAL_ELEMENT	P_OPTICAL_ELEMENT	ROMAN.META.INSTRUMENT.P_OPTICAL_ELEMENT

Each P_ keyword is explicitly defined in CRDS code as well as the CAL code data models. Relative to HST substitutions, the advantage of the ROMAN P_ keywords is that the pattern values can be defined in arbitrary combinations in the reference files instead of CRDS code.