NIRSpec Internal Lamp Template Parameters
JWST's NIRSpec Focus template, available in the Astronomer’s Proposal Tool (APT), is used to perform Internal Lamp exposures.
Purple text indicates the parameter is Limited Access.
Boldface italics type indicates the name of an APT parameter or a value for a parameter.
Red text indicates restrictions on a parameter.
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.
These parameters are required to obtain Internal Lamp observations. Note that this type of observation cannot be obtained as a parallel to normal science observations, but can be in parallel with slews.
In addition to the following template parameters, this template will have the Special Requirements NO PARALLEL and PARALLEL SLEW ONLY added.
For each Internal Lamp exposure in an observation, specify all the parameters listed below.
| Field | Details | Value | Notes |
|---|---|---|---|
| General Information | |||
| Observation Number | assign observation number | number | |
| Observation Label | provide observation label | text | optional |
| Observation Comments | provide observation comments | text | optional |
| Special Requirements | specify special requirements | choose from list | if needed |
| Template specific information | |||
| Operating Mode | select operating mode | choose from list | |
| Subarray | select subarray | choose from list | see Table 1 |
| MSA Configuration | select MSA configuration | ALLOPEN, ALLCLOSED | see Table 2 |
| Lamp | select a lamp | choose from list | |
| Grating | select a grating | choose from list | |
| Readout Pattern | select readout pattern | choose from list | |
| Number of Groups/Integration | specify number of groups/integration | number | |
| Number of Integrations/Exposure | specify number of integrations/exposure | number | |
General information
The following parameters are generic to all templates, and are not discussed in this article: Observation Number, Observation Label, Observation Comments, and Special Requirements.
Operating Mode
OPERATING MODE [OPMODE] = MSASPEC, IFU, IMAGE, FIXEDSLIT, BRIGHTOBJ, GRATING_ONLY
Select the OPERATING MODE to be used for the exposure. If dispersed data is desired as seen through the MSA, select MSASPEC. If dispersed data is desired as seen through the IFU, select IFU. If imaging data is desired, select IMAGE. If dispersed data is desired through the Fixed Slit, select FIXEDSLIT. If dispersed data is desired through the large square aperture (S1600A1), select BRIGHTOBJ. GRATING_ONLY is not allowed when the EXPOSE ONLY special requirement is used.
Subarray
SUBARRAY [SUBARRAY] = FULL, ALLSLITS, SUBS200A1, SUBS200A2, SUBS200B1, SUBS400A1, SUB2048, SUB1024A, SUB1024B, SUB512, SUB512S, SUB32
This parameter specifies the subarray that is to be read out for each detector. Some subarrays are unavailable depending on selection of OPERATING MODE (see Table 1 for details).
Table 1. Subarrays for NIRSpec Internal Lamp Observations
| Operating mode | ||||||
|---|---|---|---|---|---|---|
| Subarray | IMAGE | MSASPEC | IFU | FIXEDSLIT | BRIGHTOBJ | GRATING_ONLY |
FULL | X | X | X | X | X | |
ALLSLITS | X | X | ||||
SUBS200A1 | X | X | ||||
SUBS200A2 | X | X | ||||
SUBS200B1 | X | X | ||||
SUBS400A1 | X | X | ||||
SUB2048 | X | X | X | |||
SUB1024A | X | X | X | |||
SUB1024B | X | X | X | |||
SUB512 | X | X | X | |||
| SUB512S | X | X | ||||
| SUB32 | X | |||||
MSA Configuration
MSA CONFIG = ALLOPEN, ALLCLOSED
Select the configuration for the micro-shutter assembly (MSA). For this template, the MSA CONFIGURATION may be ALLOPEN or ALLCLOSED (see Table 2).
Table 2. MSA configuration options
| Operating Mode | MSA Configurations |
|---|---|
| MSASpec | ALLOPEN, ALLCLOSED |
| IMAGE | ALLOPEN, ALLCLOSED |
| FIXEDSLIT | ALLCLOSED (default) |
| BRIGHTJOB | ALLCLOSED (default) |
| GRATING ONLY | – |
| IFU | – |
Lamp
LAMP [LAMP] = NONE, FLAT1, FLAT2, FLAT3, FLAT4, FLAT5, LINE1, LINE2, LINE3, LINE4, REF, TEST
Select the lamp you wish to use for the exposure.
Grating
GRATING [GRATING] = G140M, G235M, G395M, G140H, G235H, G395H, PRISM, MIRROR
If the OPERATING MODE is MSASPEC, FIXEDSLIT, IFU, or BRIGHTOBJ select the grating you wish to use for the exposure. Note: If OPERATING MODE = IMAGE, the grating will not be selectable; the MIRROR will be automatically used instead. If OPERATING MODE = BRIGHTOBJ, MIRROR is not available.
Note for developer: In this case, APT needn't populate the grating field in the sql export; it will be set to NULL by the database.
Exposure Specifications
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, NRSIRS2, NRSIRS2RAPID
This field specifies the readout pattern to be used to obtain the data. The IRS2 readout patterns will only be available when SUBARRAY=FULL has been chosen.
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 100s overhead.
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.