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.
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.
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:
|assign observation number|
|Observation Label||provide observation label||text||optional|
|Observations Comments||provide observation comments||text||optional|
|select Target Name||choose from list||from Target List|
|specify special requirements||choose from list||if needed|
|Template Specific Information|
|MIMF Search||select search aperture||choose from list|
|select MSA configuration||ALLOPEN, ALLCLOSED|
|Subarray||default value||FULL, SUB32||depends on choice of MIMF Search|
|Readout Pattern||select Readout Pattern||NRS, NRSRAPID|
|Number of Groups/Integration||specify number of groups/integration||number|
|Number of Integrations||specify number of integrations/exposure||number|
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 = 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 = 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.
For each exposure to be executed, specify the READOUT PATTERN, NUMBER OF GROUPS/INTEGRATION, and the NUMBER OF INTEGRATIONS/EXPOSURE.
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.
Version 2 (April 19, 2019)
- Editorial change (moved change log to main article)
Version 1 (April 12, 2017)
This is the converted Word File from Chapter 60.
JWST NIRSpec Multi-Instrument, Multi-Field Imaging Template
JWST NIRSpec Multi-Instrument, Multi-Field Imaging Template Parameters