JWST's NIRCam Engineering Imaging template, available in the Astronomer’s Proposal Tool (APT), is used for calibration observations for the NIRCam instrument.

Introduction

The NIRCam Engineering Imaging template is to be used for commissioning and calibration activities, including some that are not necessarily anticipated at this time, requiring a template that supports highly flexible planning of observations outside the allowed scope of the science templates. This flexibility includes using any combination of filter- and pupil-wheel element, wider range of MULTIACCUM parameters, and subarray imaging on either module. This template will also likely be useful for planning unusual science observations not supported in the standard templates, and for testing proposed changes to existing templates. 

The following parameters are used to define NIRCam Engineering Imaging observations. If this template will be used for Multi-Instrument Multi-Field (MIMF) observations, you will need to add the Special Requirement WAVEFRONT SENSING = SENSING_ONLY .

General Information   

The following parameters are generic to all templates, and are not discussed in this article: Observation Number, Observation Label , Observations Comments, Target Name, Mosaic Properties  , and Special Requirements. 

Target Name  

Select the TARGET NAME [TBD] from the list of targets previously entered (see list of targets).

Module

MODULE [MODULE] = A, B, ALL

This parameter specifies the module(s) to be used to obtain the data.

Subarray

SUBARRAY [SUBARRAY] = for values see Table 1

This parameter specifies the region of the SCA that is to be read out.  All subarrays defined in the NIRCam Imaging, Photometric Time Series, Grism Time Series, Wide-field Grism Imaging and Darks templates, and in the WFSC templates, should be supported in this template. This template need not support the subarrays from the NIRCam Coronagraphic Imaging template.

Table 1. Subarrays for NIRCAM Engineering Imaging

Note for developer: Subarray rows/columns are provided in the PRD NIRCam_Subarrays table.

Subarrays may be specified on either NIRCam module, but if MODULE=ALL is selected then the only allowed value for SUBARRAY is FULL.

Module B with GRISMR

The fiducial points for MODULE B, GRISMR subarrays are optimized for the F322W2 filter.

There is a warning when all of the following are selected: MODULE=B, SUBARRAY=any SUBGRISM, PUPIL=GRISMR, and FILTER is not F322W2.

Number of Output Channels

NUMBER OF OUTPUT CHANNELS=1, 4

Allowed values depend on the selected subarray as shown in Table 2. 

Table 2. Allowed values for Number of Output Channels

Dither Patterns

The following parameters define the dither pattern for NIRCam Engineering Imaging.

Primary Dither Type

PRIMARY DITHER TYPE [DITHER_FOV] = NONE, FULL, FULLBOX, INTRAMODULE, INTRAMODULEBOX, INTRAMODULEX, INTRASCA, SUBARRAY_DITHER, WFSC

Note for developers: PRIMARY DITHER TYPE should be a required field and there should be no default value (i.e. do not make NONE the default).

This parameter specifies the type of primary dither pattern (see Table 3).

Table 3. Primary Dither Type Available for NIRCam Engineering Imaging

None

This value indicates no dithering will be performed.

Full

The following parameter is needed to specify the FULL dither.

Primary Dithers

PRIMARY DITHERS [PRIMARY_DITHERS] = 3TIGHT, 3, 6, 9, 15, 21, 27, 36, 45

This parameter indicates the number of steps in the primary dither (see Table 4).

Table 4. PRIMARY DITHERS available for PRIMARY DITHER TYPE=FULL

Fullbox

The following parameter is needed to specify the FULLBOX dither.

Primary Dithers

PRIMARY DITHERS [PRIMARY_DITHERS] = 2TIGHTGAPS, 3TIGHTGAPS, 4TIGHT, 4, 5TIGHT, 6TIGHT, 6, 8NIRSPEC 

This parameter indicates the number of steps in the primary dither.

Intramodule

The following parameter is needed to specify the INTRAMODULE dither.

Primary Dithers

PRIMARY DITHERS = 3, 4, 6, 8, 12, 16

This parameter indicates the number of steps in the primary dither.

Intramodulebox

The following parameter is needed to specify the INTRAMODULEBOX dither.

Primary Dithers

PRIMARY DITHERS [PRIMARY_DITHERS] = 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16

This parameter indicates the number of steps in the primary dither.

Intramodulex

The following parameter is needed to specify the INTRAMODULEX dither.

Primary Dithers

PRIMARY DITHERS [PRIMARY_DITHERS] = 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 

This parameter indicates the number of steps in the primary dither.

Intrasca

The following parameters are needed to specify the INTRASCA dither.

Note to developer: Populate CAMERA=SHORT until the details are worked out.

Primary Dithers

PRIMARY DITHERS = 2, 3, 4, 5, 7, 9, 13, 17, 25

This parameter specifies the number of primary dither points.

Dither Size

DITHER SIZE [DITHER_SIZE] = 8" (SMALL), 16" (MEDIUM), 24" (LARGE)

This parameter specifies the size of the dither.

Subarray_dither

The following parameter is needed to specify the SUBARRAY_DITHER dither.

Primary Dithers

PRIMARY DITHERS [PRIMARY_DITHERS] = 2, 3, 4 

This parameter indicates the number of steps in the primary dither.

WFSC

The following parameters are needed to specify the WFSC dither.

WFSC Primary Dithers

WFSC PRIMARY DITHERS = 2PLUS, 2MINUS

This parameter specifies the primary dither pattern.

Subpixel Dither Type

SUBPIXEL DITHER TYPE [SUBPIXEL_DITHER_TYPE] = STANDARD (default) , SMALL-GRID-DITHER

 This parameter specifies the subpixel dither type.

Standard   

The following parameter is needed to specify the STANDARD subpixel dither.

Subpixel Positions

SUBPIXEL POSITIONS [SUBPIXEL_POSITIONS] = 1, 2, 3, 4, 5, 7, 9, 12, 16, 20, 24, 30, 36, 48, 64

This parameter specifies the secondary dither points used for every primary dither point and is allowed for all PRIMARY DITHER TYPE values, including NONE but not WFSC.

Small Grid Dither   

The following parameter is needed to specify the SMALL-GRID-DITHER subpixel dither.

Small Grid Dithers     

SMALL-GRID-DITHER [SMALL_GRID_DITHER] = 1 (default), 2, 3, 4, 5, 6, 7, 8, 9

This parameter specifies the secondary dither points used fore every primary dither point and is allowed for all PRIMARY DITHER TYPE values, including NONE.

Note for developers: see Appendix F2 (link) for dithering details.

Pupils and Filters

For each exposure to be executed at each position in a dither pattern, specify the PUPIL/FILTER, READOUT PATTERN, NUMBER OF GROUPS/INTEGRATION, and NUMBER OF INTEGRATIONS/EXPOSURE.  Note that if only one exposure duration is specified, and this will be used with both the long- and short-wavelength cameras, despite the fact that they will have different filters/pupils.

Short Camera Pupil Name

PUPIL [PUPILSHORT] = CLEAR, MASKRND, MASKBAR, MASKIPR, F162M, F164N, GDHS0, GDHS60, PINHOLES, WLP8, WLM8, FLAT

Select the name of each pupil you wish to use. If the MODULE = ALL, the same pupil will be used in both modules.

Short Camera Filter Name

FILTER [FILTSHORT] = F070W, F090W, F115W, F150W, F150W2, F200W, F140M, F182M, F210M, F187N, F212N, WLP4

Select the name of each filter you wish to use. If the MODULE = ALL, the same filter will be used in both modules. 

Long Camera Pupil Name

PUPIL [PUPILLONG] = CLEAR, MASKRND, MASKBAR, MASKIPR, F323N, F405N, F466N, F470N, GRISMR, GRISMC, PINHOLES, FLAT

Select the name of each pupil you wish to use. If the MODULE = ALL, the same pupil will be used in both modules.

Long Camera Filter Name

FILTER [FILTLONG] = F277W, F322W2, F356W, F444W, F250M, F300M, F335M, F360M, F410M, F430M, F460M, F480M

Select the name of each filter you wish to use. If the MODULE = ALL, the same filter will be used in both modules.

Note for developers: We may need to allow certain filter combinations for GO use on a limited-access basis.

Note for developers: Because some combinations require different apertures, and only one aperture is allowed per observation, a reactive check is needed to alert the user if they have selected a combination requiring different apertures (which are documented in Appendix H (link)).

Readout Pattern

READOUT PATTERN [READOUT PATTERN] = RAPID, BRIGHT1, BRIGHT2, SHALLOW2, SHALLOW4, MEDIUM2, MEDIUM8, DEEP2, DEEP8

This field specifies the readout pattern to be used to obtain the data. Note that for MODULE=ALL, READOUT PATTERN=RAPID or BRIGHT2, and SUBARRAY=FULL, NGROUPS must be less than or equal to 4 and NINTS must be 1.

Number of Groups/Integration

NUMBER OF GROUPS/INTEGRATION [NGROUPS] specifies the number of groups in an integration. See Table 4 for the maximum values.

Number of Integrations/Exposure

NUMBER OF INTEGRATIONS/EXPOSURE [NINTS] field specifies the number of times the integration is repeated. See Table 5 for the maximum values.

Table 5. Maximum Number of Integrations/Exposure and Groups/Integration for Engineering Imaging 

Note that the restrictions on the RAPID + ALL and BRIGHT2 + ALL exposures are imposed by bandwidth limitations of the on-board data acquisition system, and so cannot be increased beyond the values shown above.

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