Reference Files

The ami_analyze step uses:

• THROUGHPUT Reference File

• NRM Reference File

THROUGHPUT Reference File

REFTYPE:

THROUGHPUT

Data model:

ThroughputModel

The THROUGHPUT reference file contains throughput data for the filter used in the AMI image.

Reference Selection Keywords for THROUGHPUT

CRDS selects appropriate THROUGHPUT references based on the following keywords. THROUGHPUT is not applicable for instruments not in the table. All keywords used for file selection are required.

Instrument	Keywords
NIRISS	INSTRUME, FILTER, DATE-OBS, TIME-OBS

Standard Keywords

The following table lists the keywords that are required to be present in all reference files. The first column gives the FITS keyword names. The second column gives the jwst data model name for each keyword, which is useful when using data models in creating and populating a new reference file. The third column gives the equivalent meta tag in ASDF reference file headers, which is the same as the name within the data model meta tree (second column).

FITS Keyword	Data Model Name	ASDF meta tag
AUTHOR	model.meta.author	author
DATAMODL	model.meta.model_type	model_type
DATE	model.meta.date	date
DESCRIP	model.meta.description	description
FILENAME	model.meta.filename	N/A
INSTRUME	model.meta.instrument.name	instrument: {name}
PEDIGREE	model.meta.pedigree	pedigree
REFTYPE	model.meta.reftype	reftype
TELESCOP	model.meta.telescope	telescope
USEAFTER	model.meta.useafter	useafter

Note

More information on standard required keywords can be found here at Standard Required Keywords.

Type Specific Keywords for THROUGHPUT

In addition to the standard reference file keywords listed above, the following keywords are required in THROUGHPUT reference files, because they are used as CRDS selectors (see Reference Selection Keywords for THROUGHPUT):

Keyword	Data Model Name
FILTER	model.meta.instrument.filter

Reference File Format

THROUGHPUT reference files are FITS files with one BINTABLE extension. The FITS primary data array is assumed to be empty. The format of the file is as follows:

EXTNAME	XTENSION	NAXIS	Dimensions	Data type
THROUGHPUT	BINTABLE	2	TFIELDS = 2	N/A

The table extension contains two columns, giving wavelength and throughput values for a particular filter:

Column name	Data type	Units
wavelength	float	Angstroms
throughput	float	(unitless)

NRM Reference File

REFTYPE:

NRM

Data model:

NRMModel

The NRM reference file contains a 2-D model of the pupil mask.

Reference Selection Keywords for NRM

CRDS selects appropriate NRM references based on the following keywords. NRM is not applicable for instruments not in the table. All keywords used for file selection are required.

Instrument	Keywords
NIRISS	INSTRUME, DATE-OBS, TIME-OBS

Standard Keywords

The following table lists the keywords that are required to be present in all reference files. The first column gives the FITS keyword names. The second column gives the jwst data model name for each keyword, which is useful when using data models in creating and populating a new reference file. The third column gives the equivalent meta tag in ASDF reference file headers, which is the same as the name within the data model meta tree (second column).

FITS Keyword	Data Model Name	ASDF meta tag
AUTHOR	model.meta.author	author
DATAMODL	model.meta.model_type	model_type
DATE	model.meta.date	date
DESCRIP	model.meta.description	description
FILENAME	model.meta.filename	N/A
INSTRUME	model.meta.instrument.name	instrument: {name}
PEDIGREE	model.meta.pedigree	pedigree
REFTYPE	model.meta.reftype	reftype
TELESCOP	model.meta.telescope	telescope
USEAFTER	model.meta.useafter	useafter

Note

More information on standard required keywords can be found here at Standard Required Keywords.

Type Specific Keywords for NRM

In addition to the standard reference file keywords listed above, the following keywords are required in NRM reference files, because they are used as CRDS selectors (see Reference Selection Keywords for NRM):

Keyword	Data Model Name
EXP_TYPE	model.meta.exposure.type

Reference File Format

NRM reference files are FITS format, with one IMAGE extension. The FITS primary HDU does not contain a data array. The format and content of the file is as follows:

EXTNAME	XTENSION	NAXIS	Dimensions	Data type
NRM	IMAGE	2	1024 x 1024	float

The NRM array contains the 2-D image representing the geometry of the non-redundant mask in the pupil wheel of NIRISS. This mask enables the Aperture Masking Interferometry (AMI) mode.