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.

Introduction

 Format definitions...

Purple text indicates the parameter is Limited Access.

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

(warning)Red text indicates restrictions on a parameter.

(red star) 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:

FieldDetailsValues Notes
General Information   
Observation Numberassign observation number

number


Observation Label provide observation labeltextoptional
Observation Commentsprovide observation commentstextoptional
Target Nameselect Target Namechoose from listfrom Target List

ETC Wkbk. Calc. ID

specify ETC Workbook Calculation IDnumberfor science exposures (optional) and target acquisition exposures
Special Requirementsspecify special requirementschoose from listif needed
Template Specific Information   
Target Acquisition Exposure
Acquisition Targetselect acquisition targetchoose from listif offset target
Acquisition Subarraydefault valueSUB32TATSGRISM
Acquisition Filterdefault valueF335M
Acquisition Readout Patternselect acquisition readout patternchoose from list
Acquisition Number of Groups/Integrationselect number of groups per integrationchoose number from list
Acquisition Number of Integrations/Exposureselect number of integrations per exposure1only allowed value
Science Exposure
select a module

A

 only allowed value
select subarray

choose from list


specify number of detector output channels

1 or 4


specify number of exposures per dither

number


select pupil+filter pair names

choose from lists


select readout pattern

choose from list


specify number of groups per integration

number


specify number of integrations per exposure

number


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.

General Information 

Target Acquisition 

The following parameters are used to define NIRCam Target Acquisition observations.

Acquisition Target Name 

If an offset star is to be used for the target acquisition observation, select the TARGET NAME [TACQ TARGET] from the list of 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: The TARGET NAME should default to "Same Target as Observation".

Note for developers: If the observation target is a fixed target, remove solar system targets from the acquisition target options. If the observation target is a Solar system target, remove all options from the acquisition target list except for the observation target and NONE.

Acquisition Subarray  

The acquisition SUBARRAY is SUB32TATSGRISM.

Acquisition Filter 

The Target Acquisition FILTER is F335M.

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.

Science Exposures

Module 

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 [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.

Exposure Specification 

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

CLEAR+WLP4


GRISMR+F277W

WLP8+F070W
GRISMR+F322W2
WLP8+F140M
GRISMR+F356W

WLP8+F182M


GRISMR+F444W

WLP8+F210M



WLP8+F187N



WLP8+F212N



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. (warning)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. (warning)The range is 1 - 65535.

Note for developer: APT should generate a warning if the visit duration is greater than 100 hours.

Change log

 Click here to expand...

The initial version of this chapter was provided by Marsha Allen.


Version 10 (September 24, 2019)

  1. PROPINSTJWST-88134 - Added description of TA=NONE option to Acquisition Target Name section.
  2. PROPINSTJWST-87170 - Added two new SW filters.


Version 9 (April 17, 2019)

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


Version 8 (December 21, 2018)

  1. PROPINSTJWST-91122 - Added developer note  in Acquisition Target section restricting acquisition target options for fixed vs. solar system observations.


Version 7 (December 27, 2017)

  1. PR 89483 - added restriction on Acq Target for SS observations
  2. PR 88411 - revised developer note to add TSO requirement


Version 6 (December 21, 2017)

  1. PR 89646 - updated the Acq Subarray name


Version 5 (September 5, 2017)

  1. PR 87895 - updated Exposure field labels to Groups/Integration and Integrations/Exposure

Version 4 (May 11, 2017)

  1. PR 87783 - revised TA NGroups


Version 3 (February 21, 2017)

  1. PR 87071 - removed mosaic option


Version 2 (November 14, 2016)

  1. PR 85330 - added target acquisition


Version 1 (April 19, 2016)

This is the converted Word File from Chapter 23.