Page tree

James Webb Space Telescope User Documentation

 

 

JWST's NIRSpec Multi-Instrument, Multi-Field Imaging template, available in the Astronomer’s Proposal Tool (APT), is used for calibration observations for the NIRSpec instrument.

Introduction

NIRSpec can handle 2 types of observations in support of Multi-Instrument, Multi-Field (MIMF) wave-front sensing.  First, NIRSpec will obtain images of the PSF through the “large square” aperture (S1600A1, 1.6” X 1.6”), placing the star within a few tenths of an arcsecond from the aperture center in at least one image. Second, NIRSpec will obtain images through the “all-open” MSA, placing the star with +/- 1 pixel (0.1 arcsec) of the center of a MSA shutter in at least one image; it is also possible to obtain data with all shutters closed.  The following parameters are used to define NIRSpec MIMF observations. These MIMF activities are intended to be used during commissioning of the OTE and not during normal NIRSpec science operations.

In addition to the following template parameters, this template will have the Special Requirement WAVEFRONT SENSING added with a default value of SENSING_ONLY 

Note for developers: APT should default to include a NO PARALLEL special requirement when the template is created, but the user should be allowed to remove it if necessary.

 The NIRSpec Multi-Instrument, Multi-Field Imaging template consists of the following parameters:

FieldDetailsValues Notes
General Information   
Observation Numberassign observation number

number


 Observation Label provide observation labeltextoptional
Observations Commentsprovide observation commentstextoptional
Target Nameselect Target Namechoose from listfrom Target List
Special Requirementsspecify special requirementschoose from listif needed
Template Specific Information   
MIMF Searchselect search aperturechoose from list
 MSA Configurationselect MSA configurationALLOPEN, ALLCLOSED
Subarraydefault valueFULL, SUB32depends on choice of MIMF Search
Readout Patternselect Readout PatternNRS, NRSRAPID
Number of Groups/Integrationspecify number of groups/integrationnumber
Number of Integrationsspecify number of integrations/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,  and Special Requirements. 

Target Name  

Select the TARGET NAME [TBD] from the list of targets previously entered (see list of targets).

 MIMF search 

 MIMF SEARCH [MIMFSEARCH] = SQUARE_AP, MSAQ1, MSAQ2, MSAQ3, MSAQ4

 This parameter specifies the NIRSpec detector area where the MIMF measurements will be taken: SQUARE_AP indicates that the target will be on the  "large square" aperture (S1600, 1.6" X 1.6"),  MSAQ1 indicated that the target will be on quadrant 1 of the Micro-shutter array,  MSAQ2 indicates the target will be on quadrant 2 of the  micro-shutter array,  MSAQ3 indicates the target will be on quadrant 3 of the micro-shutter array, and MSAQ4 indicates the target will be on quadrant 4 of the micro-shutter array.  Depending on the NIRSpec detector area specified using this parameter, the appropriate image searching pattern will be executed on-board.

 Note for developers: IF MIMFSEARCH = SQUARE AP, THEN 13 images will be taken, ELSE 10 images will be taken.

 MSA Configuration 

MSA CONFIGURATION = ALLOPEN, ALLCLOSED

 When obtaining NIRSpec MIMF data using one of the MSA quadrants (MIMFSEARCH = MSAQ1, MSAQ2, MSAQ3 or MSAQ4), select the MSA configuration.


Note for developers: The SUBARRAY is not explicitly given, and its value is SUB32 for SQUARE_AP and FULL for the MSA quadrants for purposes for calculating photon collection time.

Subarray 

SUBARRAY = FULL, SUB32

This parameter is not user selectable, and is set to SUB32 when MIMF SEARCH = SQUARE_AP and FULL when MIMF SEARCH is one of the MSA quadrants.

Exposure Duration

For each exposure to be executed, specify the READOUT PATTERN, NUMBER OF GROUPS/INTEGRATION, and the NUMBER OF INTEGRATIONS/EXPOSURE.

Readout Pattern 

READOUT PATTERN [READOUT PATTERN] = NRS, NRSRAPID

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

Number of Groups/Integration

 NUMBER OF GROUPS/INTEGRATION [NGROUPS] specifies the number of groups in an integration.

Number of Integrations/Exposure

 NUMBER OF INTEGRATIONS/EXPOSURE [NINTS] specifies the number of times the integration is performed.

Change log

 Click here to expand...

Version 2 (April 19, 2019)

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


Version 1 (April 12, 2017)

This is the converted Word File from Chapter 60.

Keywords

JWST NIRSpec Multi-Instrument, Multi-Field Imaging Template

JWST NIRSpec Multi-Instrument, Multi-Field 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.

On this page

JWST Proposal Parameters

Change log

Change log