JWST's NIRSpec Dark template, available in the Astronomer’s Proposal Tool (APT), is used to obtain darks for the NIRSpec instrument.
These parameters are required to obtain Dark observations. Note that this type of observation can be obtained as a parallel to normal science observations.
For developers: users can specify one or more combinations of the parameters below for DARKs.
The following parameters are used to define NIRSpec Dark observations.
|assign observation number||number|
|Observation Label||provide observation label||text||optional|
|Observation Comments||provide observation comments||text||optional|
|specify special requirements||choose from list||if needed|
|Template specific information|
|Subarray||select subarray||choose from list|
|Readout Pattern||select readout pattern||choose from list|
|Grating||select grating||choose from list|
|Number of Groups/Integration||specify number of groups/integration||number|
|Number of Integrations/Exposure||specify number of integrations/exposure||number|
|Number of Exposures/Dither||specify the number of times to repeat the dark exposure/dither||number|
SUBARRAY [SUBARRAY] = FULL (default), ALLSLITS, SUBS200A1, SUBS200A2, SUBS200B1, SUBS400A1, SUB2048, SUB1024A, SUB1024B, SUB512
This parameter specifies the subarray that is to be read out for each detector.
For each exposure, specify the READOUT PATTERN, GRATING, NUMBER OF GROUPS/INTEGRATION, NUMBER OF INTEGRATIONS/EXPOSURE, and NUMBER OF EXPOSURES/DITHER.
READOUT PATTERN [READOUT PATTERN] = NRS, NRSRAPID, NRSIRS2, NRSIRS2RAPID
This field specifies the readout pattern to be used to obtain the data.
Note that there is a 100 second overhead associated with switching between IRS2 and non-IRS2 readout patterns in an observation.
Note that NUMBER OF GROUPS/INTEGRATION x NUMBER OF INTEGRATIONS/EXPOSURE must be less than 256 for NRISIRS2 and 1024 for NRSIRS2RAPID.
Note for developers: If there is interleaving of IRS2 and non-IRS2 readout patterns, issue a warning alerting the user to the 100 seconds overhead.
GRATING [GRATING] = G140M, G235M, G395M, G140H, G235H, G395H, PRISM, MIRROR
This field specifies the grating. This parameter is necessary because GRATING defines the location of the subarray on the detector. If SUBARRAY is FULL this field is not available.
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] field specifies the number of times the integration is performed.
Number of Exposures/Dither
NUMBER OF EXPOSURES/DITHER [NEXP] specifies the number of times the Dark exposure is performed; the range is 1-50.
Version 3 (April 19, 2019)
- Editorial change (moved change log to main article)
Version 2 (September 5, 2017)
- PR 88059 - added grating field
- PR 88968 - revised overhead time for switching between IRS and IRS2 readout patterns
- PR 88047 - added restriction on NGroups x NINTS for IRS2 readout pattern
Version 1 (June 15, 2017)