NIRCam Grism Time Series Imaging Template Parameters
JWST's NIRCam Grism Time Series Imaging template, available in the Astronomer’s Proposal Tool (APT), has parameters for specifying and scheduling observations.
Purple text indicates the parameter is Limited Access.
Boldface italics type indicates the name of an APT parameter or a value for a parameter.
Red text indicates restrictions on a parameter.
Black text indicates an important note.
Brown text indicates notes for the developers.
Green text indicates the name of the parameter used by Commanding.
Items in brackets - <value> - are required values.
Items in square brackets - [<value>] - are optional.
The NIRCam Grism Time Series Imaging template is used for the Grism time series 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 Grism Time-Series APT Template article.
The NIRCam Grism Time Series Imaging template consists of the following parameters:
|Observation Number||assign observation 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|
|Special Requirements||specify special requirements||choose from list||if needed|
|Template Specific Information|
|Target Acquisition Exposure|
|Acquisition Target||select acquisition target||choose from list||if offset target|
|Acquisition Subarray||default value||SUB32TATSGRISM|
|Acquisition Filter||select acquisition filter||F335M, F405N+F444W|
|Acquisition Readout Pattern||select acquisition readout pattern||choose from list|
|Acquisition Number of Groups/Integration||select number of groups per integration||choose number from list|
|Acquisition Number of Integrations/Exposure||select number of integrations per exposure||1||only allowed value|
|select a module|
|only allowed value|
choose from list
|specify number of detector output channels|
1 or 4
|specify number of exposures per dither|
|select pupil+filter pair names|
choose from lists
|select readout pattern|
choose from list
|specify number of groups per integration|
|specify number of integrations per exposure|
Note for developer: This template cannot be used in parallel and cannot have parallels attached to it; the NO PARALLEL special requirement should be added. The TIME SERIES OBSERVATION special requirement should also be added.
Note for developer: This template cannot be used with a mosaic.
The following parameters are generic to all templates, and are not discussed in this article: Observation Number, Observation Label, Observations Comments, Target Name, ETC Wkbk. Calc. ID, and Special Requirements.
The following parameters are used to define NIRCam Target Acquisition observations.
Acquisition Target Name
The default for this parameter is "Same Target as Observation." If an offset star is to be used for the target acquisition observation, select the TARGET NAME [TACQ TARGET] from the list of fixed targets previously entered. When the science target is a Solar System target, the acquisition target MUST be the science target. Or, if no target acquisition is needed, select ACQUISITION TARGET to be NONE.
Note for developer: If the acquisition target is different from the science target, APT should provide a warning if the distance between the ACQ and Science targets is greater than the Visit splitting distance found in the PRD. Also, if there are multiple pointings within a visit, then the rules have to apply to the greatest separation between acq target and pointing within the visit.
The acquisition SUBARRAY is SUB32TATSGRISM.
TARGET ACQUISITION FILTER [TACQ FILTER] = F335M, F405N+F444W
This parameter specifies the TARGET ACQUISITION FILTER to be used for the target acquisition.
Acquisition Readout Pattern
ACQUISITION READOUT PATTERN [TACQ PATTERN] = RAPID, BRIGHT1, BRIGHT2, SHALLOW2, SHALLOW4, MEDIUM2, MEDIUM8, DEEP2, DEEP8
This field specifies the readout pattern to be used to obtain the acquisition data.
Acquisition Number of Groups/Integration
NUMBER OF GROUPS/INTEGRATION [TACQ NGROUPS] = 3, 5, 9, 17, 33, 65
This parameter specifies the number of groups in an integration.
Acquisition Number of Integrations/Exposure
NUMBER OF INTEGRATIONS/EXPOSURE specifies the number of times the integration is repeated, and is always 1.
MODULE [MODULE] = A
There is only one choice for MODULE in this template, so there is only one long wavelength detector and two short wavelength detectors.
SUBARRAY [SUBARRAY] = FULL, SUBGRISM256, SUBGRISM128, SUBGRISM64
This parameter specifies the region of the SCA detector that is to be read out. For more details about these subarrays, see Subarray in the NIRCam Grism Time-Series APT Template article.
Number of Detector Output Channels
NUMBER OF DETECTOR OUTPUT CHANNELS [NOUTPUTS] = 1 (default), 4
This field specifies the number of detector output channels to use. For more details, see Number of Output Channels.
Note for developer: Add a label in the gui to the right of No. of Outputs to indicate the Frame Readout time.
Number of Exposures/Dither
NUMBER OF EXPOSURES/DITHER [NEXP] field specifies the number of times the exposure is to be repeated.
For each exposure specify the FILTER-PUPIL pairs, READOUT PATTERN, NUMBER OF GROUPS/INTEGRATION, and NUMBER OF INTEGRATIONS/EXPOSURE. For the filter bandpasses, see NIRCam Filters while for pupil information, see NIRCam Pupil and Filter Wheels. Note that only one exposure specification is allowed, and this will be used with both the long- and short-wavelength cameras. For more information on defining an exposure specification, see Exposure Time in the NIRCam Grism Time-Series APT Template article.
Filter and Pupil Names
Select the name of each PUPIL+FILTER [FILTSHORT, FILTLONG] pair you wish to use (one for the Short Wavelength and one for the Long Wavelength cameras) from Table 1.
Table 1. Pupil+Filter Pairs Available for NIRCam Grism Time Series Imaging
|Short Wavelength Camera Filter+Pupil||Long Wavelength Camera Filter+Pupil|
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. The range is 1 - 30, inclusive.
Number of Integrations/Exposure
NUMBER OF INTEGRATIONS/EXPOSURE [NINTS] field specifies the number of times the integration is repeated. The range is 1 - 65535.
Note for developer: APT should generate a warning if the visit duration is greater than 100 hours.
The initial version of this chapter was provided by Marsha Allen.
Version 13 (May 11, 2022)
- PROPINSTJWST-91468 Added developer note about warning for visit splitting distance to Acquisition Target Name section.
Version 12 (August 9, 2021)
- Editorial change - Anchor links fixed in parameter table by removing pagename from link.
Version 11 (December 23, 2019)
- PROPINSTJWST-89005 - Added new filter to Acquistion Filter section.
Version 10 (September 24, 2019)
- PROPINSTJWST-88134 - Added description of TA=NONE option to Acquisition Target Name section.
- PROPINSTJWST-87170 - Added two new SW filters.
Version 9 (April 17, 2019)
- Editorial change (moved change log to main article).
Version 8 (December 21, 2018)
- PROPINSTJWST-91122 - Added developer note in Acquisition Target section restricting acquisition target options for fixed vs. solar system observations.
Version 7 (December 27, 2017)
- PR 89483 - added restriction on Acq Target for SS observations
- PR 88411 - revised developer note to add TSO requirement
Version 6 (December 21, 2017)
- PR 89646 - updated the Acq Subarray name
Version 5 (September 5, 2017)
- PR 87895 - updated Exposure field labels to Groups/Integration and Integrations/Exposure
Version 4 (May 11, 2017)
- PR 87783 - revised TA NGroups
Version 3 (February 21, 2017)
- PR 87071 - removed mosaic option
Version 2 (November 14, 2016)
- PR 85330 - added target acquisition
Version 1 (April 19, 2016)
This is the converted Word File from Chapter 23.