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JWST's NIRISS Single-Object Slitless Spectroscopy (SOSS) imaging template, available in the Astronomer’s Proposal Tool (APT ), has parameters for specifying and scheduling observations.

Introduction

The NIRISS Single-Object Slitless Spectroscopy (SOSS) template is used for the SOSS mode of NIRISS, and this article describes allowed values for all parameters. Advice on how to choose values which optimize your science can be found in the NIRISS Single-Object Slitless Spectroscopy APT Template. 

The NIRISS SOSS template

 consists of the following parameters:

FieldDetailsValues Notes
General Information   
Observation Numberassign observation number

number



Observation Label provide observation labeltextoptional

Observation Comments



provide 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
select acquisition target

choose from list


Acquisition Filterdefault valueF480M
select acquisition mode

SOSSBRIGHT, SOSSFAINT


select acquisition readout pattern

NIS, NISRAPID


select number of groups per integration

choose from list


Science Exposure
select subarray

choose from list


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.

General Information  

Target Acquisition Exposure

Acquisition Target 

If an offset star is to be used for the target acquisition observation, select the ACQUISITION TARGET [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; the latter option is only allowed if SUBARRAY is FULL (see Subarray ).

Note for developers: For APT, the ACQUISITION TARGET name field should always be present, but should be defaulted to the SAME TARGET AS OBSERVATION.

Note for developers: If the  acquisition  target is different from the science  target, APT should provide an error 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.

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 Filter   

The Target Acquisition FILTER is F480M.

Acquisition Mode 

ACQUISITION MODE [TACQ MODE] = SOSSBRIGHT, SOSSFAIN

This field specifies the target acquisition mode to be used to obtain the acquisition data for a “bright” or “faint” target. In this context, "bright" refers to M-band magnitudes in the range 3.0 ≤ M ≤ 6.1 (in the Vegamag system), while "faint" refers to 6.1 ≤ M ≤ 14.5.  

Acquisition Readout Pattern 

READOUT PATTERN [TACQ PATTERN] = NIS, NISRAPI

This field specifies the readout pattern to be used to obtain the acquisition data.

Note for developer: The NIS option is only available when TACQ MODE = SOSSFAINT.

Acquisition Number of Groups/Integration

NUMBER OF GROUPS/INTEGRATION [TACQ NGROUPS] = 3, 5, 7, 9, 11, 13, 15, 17, 19

This parameter specifies the number of groups in an integration. Note that the NUMBER OF INTEGRATIONS/EXPOSURE is set to 1 for target acquisition observations.

Science Exposure 

For each exposure  specify the SUBARRAY, READOUT PATTERN, NUMBER OF GROUPS/INTEGRATION,  and NUMBER OF INTEGRATIONS/EXPOSURE. For more information on defining an exposure specification, see Exposure time.

Note developers: there is only 1 exposure allowed in an observation.

Subarray  

SUBARRAY [SUBARRAY] = SUBSTRIP256 (default), SUBSTRIP96, FULL

This parameter specifies the region of the SCA detector that is to be read out. For more details about these subarrays, see Subarray. 

Readout Pattern 

READOUT PATTERN [READOUT PATTERN] = NISRAPID (default), NIS

This field specifies the readout pattern to be used to obtain the SOSS science data. Note that NIS is only available when SUBARRAY = FULL.

Number of Groups/Integration 

NUMBER OF GROUPS/INTEGRATION [NGROUPS] specifies the number of groups in each integration. (warning)For readout pattern NIS, the range is 1-200, while for NISRAPID the range is 1-30

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 that the following parameters have only one option, and are therefore not included in the template:

ParameterValue
DisperserGR700XD

Change log

 Click here to expand...

The initial version of this chapter was provided by Lily Liu.


Version 7 (April 18, 2019)

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


Version 6 (December 21, 2018)

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


Version 5 (December 27, 2017)

  1. PR 89483 - added restriction on Acq Target for SS observations
  2. PR 88411 - added developer note about TSO and NO PARALLEL requirements


Version 4 (November 15, 2017)

  1. PR 87895 - updated Exposure field labels to Groups/Integration and Integrations/Exposure
  2. PR 87961 - updated TA Readout Pattern options to include NIS
  3. PR 87198 - added note that NIS is only available when SUBARRAY=FULL
  4. PR 88816 - updated text for Acquisition Mode


Version 3 (February 21, 2017)

PR 87071 - removed mosaics option


Version 2 (December 20, 2016)

  1. PR 85863 - updated developer note for Acquisition Target
  2. PR 85608 - removed statement about Acq Flux, and added new section to state default Acq Filter


Version 1 (March 29, 2016)

This is the converted Word File from Chapter 42.

Keywords

JWST NIRISS Single-Object Slitless Spectroscopy Template

JWST NIRISS Single-Object Slitless Spectroscopy template parameters

Format definitions

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

(warning)Red text indicates restrictions on a parameter.

Brown text indicates notes for the developers.

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

On this page

JWST Proposal Parameters

Change log

Change log