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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 .

FieldDetailsValuesNotes
General Information
Observation Numberassign observation number

number


 Observation Label
provide observation labeltextoptional
Observations Commentsprovide observation commentstextoptional
Target Nameselect Target Namechoose from listfrom Target List
Mosaic Propertiesspecify mosaic parametersnumberif needed
Special Requirementsspecify special requirementschoose from listif needed
Template Specific Information
Target Nameselect Target Namechoose from listfrom Target List
Science Exposures

Module

select Module

choose A, B, or All


Subarray

select Subarray

choose from list


Dither Pattern
Primary Dither Typeselect Dither Typechoose from list 
Primary Dithers select number of stepschoose from listfor FULL only
Primary Dithersselect number of stepschoose from listfor FULLBOX only
Primary Dithersselect number of stepschoose from listfor INTRAMODULE only
Primary Dithersselect number of stepschoose from listfor INTRAMODULEBOX only
Primary Dithersselect number of stepschoose from listfor INTRAMODULEX only
Primary Dithersselect number of stepschoose from listfor INTRASCA only
Dither Sizeselect dither sizeSMALL, MEDIUM, LARGEfor INTRASCA only
Primary Dithersselect number of stepschoose from listfor SUBARRAY_DITHER only
WFSC Primary Dithersselect number of steps2PLUS, 2MINUSfor WFSC only
Subpixel Positionsselect subpixel positions1, 2, 3 ...for STANDARD only, not valid for WFSC
Small Grid Dithersselect the small grid dither patternchoose from listfor SMALL-GRID-DITHER only




Short Camera Pupilselect pupil namechoose from list 
Short Camera Filterselect filter namechoose from list 
Long Camera Pupilselect pupil nameschoose from list 
Long Camera Filterselect filter namechoose from list 
Readout Patternselect readout patternnumber 
Number of Groups/Integrationspecify number of groups per integrationnumber 
Number of Integrations/Exposurespecify number of integrations per exposurenumber

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] = 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

SubarrayRowsColumnsModule

Imaging Subarrays

FULL

2048

2048

A, B, ALL

SUB160

160     

160

A, B

SUB320

320

320

A, B

SUB640

640

640

A, B

Photometric Time Series and Point-source Imaging Subarrays

SUB400P

400

400

A, B

SUB160P

160

160

A, B

SUB64P

64

64

A, B

Grism Time Series Subarrays

SUBGRISM256

256

2048

A, B

SUBGRISM128

128

2048

A, B

SUBGRISM64

64

2048

A, B

Wide-field Grism Imaging – subarrays are TBD.

Darks Subarrays – no additional subarrays needed..

Wavefront Sensing and Control subarrays

SUB96DHSPILA

96

96

A

SUB96DHSPILB

96

96

B

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

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 2).

Table 2. Primary Dither Type Available for NIRCam Engineering Imaging

Primary Dither Type

Description

NONE

No dithering

FULL

Covers the 40" gap between modules

FULLBOX

INTRAMODULE

Covers the 5" gaps between SCAs, but not the module gap

INTRAMODULEBOX
INTRAMODULEX

INTRASCA

Moves a target around a single SCA

SUBARRAY_DITHER

WFSC

Supports WFSC observations

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 3).

 

Table 3. PRIMARY DITHERS available for PRIMARY DITHER TYPE=FULL

Primary DithersDescription

3

3-point pattern that maximizes inner area of 2´ coverage

6

6-point pattern that maximizes  area of 4´ coverage

     (minimum 3´-coverage everywhere)

9

9-point pattern that maximizes area of 6´ coverage

     (minimum 5´-coverage everywhere)

3TIGHT

3-point pattern that maximizes depth of 3´ coverage

15

Specific patterns to take optimally flat coverage

21

27

36

45

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. (warning)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. (warning)See Table 4 for the maximum values.

 

Table 4. Maximum Number of Integrations/Exposure and Groups/Integration for Engineering Imaging 

Readout PatternMaximum Integrations/ExposureMaximum Groups/Integration

RAPID

(MODULE=ALL)

65536

1

5000

4

BRIGHT1

65536

5000

BRIGHT2

(MODULE=ALL)

65536

1

5000

4

SHALLOW2

5000

2000

SHALLOW4

5000

2000

MEDIUM2

5000

2000

MEDIUM8

5000

2000

DEEP2

5000

2000

DEEP8

5000

2000

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.

Change log

 Click here to expand...

Change Log

Version 3 (April 17, 2019)

  1. Editorial change (moved change log to main article).


Version 2 (October 9, 2017)

  1. PR 88124 - added dither patterns
  2. PR 88129 - added new options for subpixel dithers
  3. PR 87895 - updated Exposure field labels to Groups/Integration and Integrations/Exposure


Version 1 (April 11, 2017)

  1. This is the converted Word File from Chapter 29.
  2. PR 83561 - added Small Grid Dithers
  3. PR 86997 - updated Primary Dither for INTRAMODULE and INTRASCA; updated Subpixel Positions
  4. PR 86401 - updated dithers

Keywords

JWST NIRCam Engineering Imaging Template

JWST NIRCam Engineering Imaging template parameters

Format definitions

Boldface italics type indicates the name of an APT parameter or a value for a parameter.

Brown text indicates notes for the developers.

Green text indicates the name of the parameter used by Commanding.

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