NIRCam Imaging Template Parameters
JWST's NIRCam Imaging template, available in the Astronomer’s Proposal Tool (APT), has parameters for specifying and scheduling observations.
Introduction
The NIRCam Imaging template is used for the direct imaging mode of NIRCam, and this article describes allowed values for all parameters. Advice on how to choose values which optimize your science can be found in the NIRCam Imaging APT Template article.
The NIRCam Imaging template consists of the following parameters:
Field | Details | Values | Notes |
---|---|---|---|
General Information | |||
Observation Number | assign observation number | number | |
Observation Label | provide observation label | text | optional |
Observation Comments | provide observation comments | text | optional |
Target Name | select Target Name | choose from list | from Target List |
specify ETC Workbook Calculation ID | number | for science exposures (optional) and target acquisition exposures | |
Mosaic Properties | specify mosaic parameters | number | if needed |
Special Requirements | specify special requirements | choose from list | if needed |
Template Specific Information | |||
Science Exposures | |||
select module | B or ALL | ||
select subarray | choose from list | ||
select aperture | choose from list | ||
Dither Patterns | |||
select Dither Type | choose from list | ||
select number of steps | choose from list | for FULL only | |
Primary Dithers | select number of steps | choose from list | for FULLBOX only |
Primary Dithers | select number of steps | choose from list | for INTRAMODULEX only |
Primary Dithers | select number of steps | choose from list | for INTRAMODULEBOX only |
select number of steps | choose from list | for INTRAMODULE only | |
select number of steps | choose from list | for INTRASCA only | |
select dither size | choose from list | for INTRASCA only | |
Primary Dithers | select number of steps | choose from list | for SUBARRAY_DITHER only |
Subpixel Dither Type | select subpixel dither type | STANDARD, SMALL-GRID-DITHER | |
select subpixel positions | 1, 2, 3... | for STANDARD only | |
Small Grid Dithers | select the small grid dither pattern | choose from list | for SMALL-GRID-DITHER only |
Filters | |||
select filter name(s) | choose from list | ||
select readout pattern | choose from list | ||
specify number of groups/integration | number | ||
specify number of integrations/exposure | number |
General Information
The following parameters are generic to all templates, and are not discussed in this article: Observation Number, Observation Label, Observation Comments, Target Name, ETC Wkbk. Calc. ID, Mosaic Properties, and Special Requirements.
Science Exposures
Module
MODULE [MODULE] = B, ALL
This parameter specifies the module(s) to be used to obtain the data.
Subarray
SUBARRAY [SUBARRAY] = FULL, FULLP, SUB64P, SUB160, SUB160P, SUB320, SUB400P, SUB640
This parameter specifies the region of the SCA detector that is to be read out.
Subarrays other than FULL can only be specified if MODULE is B.For more details about these subarrays, see Subarray in NIRCam Imaging APT Template.
Note to developer: If SUBARRAY= SUB64P, provide a diagnostic warning with the following text:
"The overlap of the SW and LW FOVs for the SUB64P subarrays is 1.16 x 1.87 arcseconds. Your target is likely to be displaced from the center of that region by 0.3 - 0.45 arcseconds (1-sigma). Consider using dithers or a mosaic to guarantee full spatial coverage of your target, and adequate sky coverage around it, in both channels. Use of the Time Series template, which includes target acquisition, will provide very accurate positioning, but does not offer dither or mosaic options."
Target Placement
TARGET PLACEMENT= MODULE GAP (default), MODULE A(A3 CORNER), MODULE B(B4 CORNER)
Select where the target will be placed relative to the detectors (see NIRCam Imaging APT Template).
- TARGET PLACEMENT is available only when MODULE=ALL and SUBARRAY=FULL.
- TARGET PLACEMENT is not available for parallel observations.
- For TARGET PLACEMENT=MODULE A(A3 CORNER), an implicit FIDUCIAL POINT OVERRIDE NRCAS_FULL special requirement is added.
- For TARGET PLACEMENT=MODULE B(B4 CORNER), an implicit FIDUCIAL POINT OVERRIDE NRCBS_FULL special requirement is added.
Dither Patterns
Most NIRCam Imaging observations will require dithering; see Dither Parameters in the NIRCam Imaging APT Template article for details.
Primary Dither Type
PRIMARY DITHER TYPE [DITHER_FOV] = NONE, FULL, FULLBOX, INTRAMODULE, INTRAMODULEX, INTRAMODULEBOX, INTRASCA, SUBARRAY_DITHER
This parameter specifies the type of primary dither pattern.
For observations with a single dither point, APT provides a warning. Total Dithers are displayed on the Filters table. The warning is not provided if the NIRCam Imaging observation is in a pure parallel, or is non-prime in a coordinated parallel with a prime that is not dithered.
Note to developer: PRIMARY DITHER TYPE should be a required field, and there should be no default value (i.e. do not make NONE the default).
Note to developer: If SUBARRAY=FULL and MODULE=ALL, do not offer PRIMARY DITHER TYPE=SUBARRAY_DITHER. If SUBARRAY=FULL and MODULE=B, do not offer PRIMARY DITHER TYPE=FULL or FULLBOX. If SUBARRAY=SUB640, SUB320, or SUB160 and MODULE=B offer only PRIMARY DITHER TYPE=INTRASCA, INTRAMODULEBOX, or SUBARRAY_DITHER. If SUBARRAY=SUB400P, SUB160P, or SUB64P and MODULE=B offer only PRIMARY DITHER TYPE=INTRAMODULEBOX or SUBARRAY_DITHER.
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.
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.
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.
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.
Intramodule
The following parameter is needed to specify the INTRAMODULE dither.
Primary Dithers
PRIMARY DITHERS [PRIMARY_DITHERS] = 3, 4, 6, 8, 12, 16
This parameter specifies the number of primary dither points.
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 [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 pattern.
Note to developer: Change to add the size to the name can be for the GUI only and the original value can be what goes to the database.
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.
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 (default) , 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.
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 for every primary dither point and is allowed for all PRIMARY DITHER TYPE values, including NONE.
Note to developer: see NIRCam Dither Details for dithering details.
Filters
Exposures are grouped by filter pairs; for the filter bandpasses, see NIRCam Filters. For each set of exposures to be executed at each position in a dither pattern, specify the FILTER, READOUT PATTERN, NUMBER OF GROUPS/INTEGRATION, and the NUMBER OF INTEGRATIONS/EXPOSURE. Note that 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. For more information on defining an exposure specification, see Filters and Exposures in the NIRCam Imaging APT Template article.
Filter Name
Select the name of each FILTER [FILTLONG, FILTSHORT] pair you wish to use (one for the Long Wavelength and one for the Short Wavelength cameras; see Table 1)
. If the MODULE is ALL, the same filter pair will be used in both modules.
Table 1. Filters Available for NIRCam Imaging
Short Wavelength Camera Filter | Long Wavelength Camera Filter | |
---|---|---|
Single Filters | Single Filters | |
F070W | F277W | |
F090W | F322W2 | |
F115W | F356W | |
F150W | F444W | |
F150W2 | F250M | |
F200W | F300M | |
F140M | F335M | |
F182M | F360M | |
F210M | F410M | |
F187N | F430M | |
F212N | F460M | |
F480M | ||
Crossed Filters | Crossed Filters | |
F162M+F150W2 | F323N+F322W2 | |
F164N+F150W2 | F405N+F444W | |
F466N+F444W | ||
F470N+F444W |
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.
Number of Groups/Integration
NUMBER OF GROUPS/INTEGRATION [NGROUPS] specifies the number of groups in an integration
. See Table 2 for the values as a function of READOUT PATTERN.
Table 2. Number of Groups/Integration for Imaging Observations
Readout Pattern | Number of Groups/Integration | Number of Integrations/Exposure (SUBARRAY = FULL) | Number of Integrations/Exposure (all other SUBARRAYs) |
---|---|---|---|
RAPID (MODULES=B) | 1-10 | 1-10 | 1-200 |
RAPID (MODULES=ALL) | 2 1 | 1-2 1-20 | N/A N/A |
BRIGHT1 | 1-10 | 1-10 | 1-200 |
BRIGHT2 (MODULES=B) | 1-10 | 1-10 | 1-200 |
BRIGHT2 (MODULES=ALL) | 2-10 | 1-10 | N/A |
SHALLOW2 | 1-10 | 1-10 | 1-200 |
SHALLOW4 | 1-10 | 1-10 | 1-200 |
MEDIUM2 | 1-10 | 1-10 | 1-200 |
MEDIUM8 | 1-10 | 1-10 | 1-200 |
DEEP2 | 1-20 | 1-10 | 1-200 |
DEEP8 | 1-20 | 1-10 | 1-200 |
Number of Integrations/Exposure
NUMBER OF INTEGRATIONS/EXPOSURE [NINTS] field specifies the number of times the integration is repeated
. See Table 2 for the values as a function of READOUT PATTERN.