MIRI Coronagraphic Imaging Template Parameters
JWST's MIRI Coronagraphic Imaging template, available in the Astronomer’s Proposal Tool (APT), has parameters for specifying and scheduling observations.
Introduction
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.
The MIRI Coronagraphic Imaging template is to be used for all observations using the coronagraphic imaging mode of MIRI, and this article describes allowed values for all parameters. Advice on how to choose values which optimize your science can be found in the MIRI Coronagraphic Imaging APT Template and in MIRI Coronagraphic Imaging.
The MIRI Coronagraphic Imaging template consists of the following parameters:
| Field | Details | Values | Notes |
|---|---|---|---|
| General Information | |||
| Observation Number | assign observation number | number | |
| Observation Label | provide observation label | text | optional |
| Observation Comments | provide observation comments | text | optional |
| Target Name | select Target Name | choose from list | from Target List |
| specify ETC Workbook Calculation ID | number | for science exposures (optional) and target acquisition exposures | |
| Special Requirements | specify special requirements | choose from list | if needed |
| Template Specific Information | |||
| Target Acquisition Exposure | |||
| Target Acquisition Quadrant | select target acquisition quadrant | number | |
| select filter | choose from list | ||
| Acquisition Readout Pattern | select acquisition readout pattern | choose from list | |
| Acquisition Number of Groups/Integration | select number of groups per integration | number | |
| Acquisition Number of Integrations/Exposure | select number of integrations per exposure | 1 | only allowed value |
| Coronagraphic Exposures | |||
| Science Observation Coronagraphic Mask/Filter | select mask/filter | choose from list | |
| Readout Pattern | select readout pattern | choose from list | |
| Number of Groups/Integration | specify number of groups per integration | number | |
| Number of Integrations/Exposure | specify number of integrations per exposure | number | |
| Number of Exposures/Dither | specify number of times to repeat the exposure for each dither position | number | |
| select dither type | choose from list | ||
| Repeat Observation | specify if repeat acq and observation needed | YES, NO | |
| PSF Reference Observations | |||
| This is a PSF Reference Observation | indicate if PSF | ||
| PSF Reference Observations | select PSF Observations | choose from list | |
| Additional Justification | indicate that there will be no specific PSF Obs | ||
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, ETC Wkbk. Calc. ID, and Special Requirements.
Target Acquisition
The following parameter is used to define MIRI Target Acquisition observations. Note that for Coronagraphic Imaging, the science target is used for the acquisition (unlike NIRCam Coronagraphy, where an offset target may be used). For more information on defining a target acquisition specification, see MIRI Coronagraphic Imaging Target Acquisition.
Note for developers: Target acquisition with the LYOT coronagraph will use the MASKLYOT subarray. With the 1550 4QPM will use the MASK1550 subarray. Same for 1140 and 1065.
Target Acquisition Quadrant
Select the TARGET ACQUISITION QUADRANT [TACQ QUADRANT] (1 - 4) in which the initial target acquisition will be performed.
Target Acquisition Filter
TARGET ACQUISITION FILTER [TACQ FILTER] = F560W, F1000W, F1500W, FND
This parameter specifies the TARGET ACQUISITION FILTER to be used for the target acquisition.
Acquisition Readout Pattern
READOUT PATTERN [TACQ PATTERN] = FAST (default), FASTGRPAVG
This field specifies the readout pattern to be used to obtain the acquisition data.
Acquisition Number of Groups/Integration
NUMBER OF GROUPS/INTEGRATION [TACQ NGROUPS] = 4, 6, 8, 10, 12, 22, 36, 44, 66, 86, 98
This field specifies the number of groups in an integration.
Acquisition Number of Integrations/Exposure
The NUMBER OF INTEGRATIONS/EXPOSURE [TACQ NINTS] is set to 1 for target acquisition observations.
Coronagraphic Exposures
For the exposures to be executed, specify the MASK/FILTER, READOUT PATTERN, NUMBER OF GROUPS/INTEGRATION, NUMBER OF INTEGRATIONS/EXPOSURE, and the NUMBER OF EXPOSURES/DITHER. For more information on defining an exposure specification, see Exposure time. Optional DITHER TYPE and REPEAT OBSERVATION may also be selected.
Coronagraphic Mask/Filter Combination
CORONAGRAPHIC MASK [CORON] /FILTER [FILTER] = 4QPM/F1065C, 4QPM/F1104C, 4QPM/F1550C, LYOT/F2300C
Select the coronagraphic mask and filter combination you wish to use to obtain the data; for the mask properties, see MIRI Coronagraph Masks, while for the filter bandpasses, see Coronagraphic filters.
Note for developers: The following SUBARRAY values are used for the specified mask: 4QPM/F1065C - MASK1065, 4QPM/F1104C - MASK1140, 4QPM/F1550C - MASK1550, and LYOT/F2300C - MASKLYOT.
Note for developers: for now, only 1 mask/filter can be selected for an observation. However, in the future, it may be possible to use all 4. Also, APT will need to break the selection into their component values for the scripts. Also note that only 1 exposure time per Mask/Filter will be supported.
Readout Pattern
READOUT PATTERN [READOUT PATTERN] = FAST (default), FASTGRPAVG
This field specifies the readout pattern to be used to obtain the data.
Number of Groups/Integration
NUMBER OF GROUPS/INTEGRATION [NGROUPS] specifies the number of groups in each integration.
NUMBER OF GROUPS/INTEGRATION must be 2 or greater.
If READOUT PATTERN = FASTGRPAVG, it is recommended that NUMBER OF GROUPS/INTEGRATION be at least 4. For all other READOUT PATTERNs, a number of 2-4 is allowed but not recommended.
Number of Integrations/Exposure
NUMBER OF INTEGRATIONS/EXPOSURE [NINTS] field specifies the number of times the integration is repeated in each exposure; default = 1.
Number of Exposures/Dither
NUMBER OF EXPOSURES/DITHER [NEXP] specifies the number of times the exposure is to be repeated at each dither position. The default value is 1.
If NUMBER OF EXPOSURES/DITHER > 1, the NO PARALLEL special requirement is required.
Note for developer: If NUMBER OF EXPOSURES/DITHER > 1. provide the following error: " The Special Requirement NO PARALLEL must be used with this Observation." and the following diagnostic explanation: "The NO PARALLEL requirement is required for Coordinated Parallels; Time Series observations; external observations with NUMBER OF EXPOSURES/DITHER > 1 and dithering; NIRSpec observations with Auto Calibrations; NIRCam Grism Time Series; and engineering templates (FGS Internal Flat, MIRI Anneal, MIRI External Flat, NIRSpec Internal Lamp, NIRSpec MSA Masking, NIRSpec MSA Anneal, NIRISS Internal Flat, all WFSC)."
Dither Type
DITHER TYPE [PATTERN_TYPE] = None (default), 5-POINT-SMALL-GRID, 9-POINT-SMALL-GRID
This parameter specifies the type of dithering needed.
Repeat Observation
REPEAT OBSERVATION = NO (default), YES
If YES is selected, the target acquisition (followed by a science exposure) will be repeated starting in the quadrant diagonally across the central spot from the initial TARGET ACQUISITION QUADRANT, as follows:
| First Quadrant | Second Quadrant |
|---|---|
| 1 | 3 |
| 2 | 4 |
| 3 | 1 |
| 4 | 2 |
Note for developer:
- Disable REPEAT OBSERVATION option if TARGET ACQUISITION QUADRANT is not selected.
- When TARGET ACQUISITION QUADRANT has a valid value, show the text "(with Target Acquisition in quadrant X)" where X is the value of the diagonal quadrant.
- Store the second TACQ QUADRANT value instead of this boolean in the database.
- If the exposure parameters are chosen such that the Observation results in multiple visits give an error.
PSF Reference Observations
Coronagraphic observations generally have two science observations with an APERTURE PA OFFSET between them of 1-14 degrees as well as an associated PSF reference observation. These observations should be done back-to-back using the SEQUENCE NON-INT special requirement. Warning and errors will help guide the user to correctly set up these links.
This is a PSF Reference Observation
Choosing this option indicates that this observation is a PSF observation.
Note to developer: If this option is chosen, display on the GUI "exclusive access period will be 0 months".
PSF Reference Observations
If this is a science observation, designated PSF Reference Observations must be selected from this list. (The exception is for a "self reference survey" where all observations serve as PSF observations for each other. In this case select the science observations which will be used.)
Note to developer: Only list observations which use the same instrument, same coronagraphic mask, and same filter (ordered so that ones with the PSF Reference Observation checked come first and then the ones without the check).
Additional Justification
Choosing this option indicates that this observation will not have a separate designated PSF observation because it is part of a self reference survey which will be described in the science justification.
Note to developer: It is an error to have nothing checked in the PSF Reference Observations. And it is still an error for a science observation to only choose other science observations and not choose a designated PSF observation, but in that case choosing the Additional Justification option replaces that error with a warning that a self reference survey must be justified.This field specifies the number of groups in an integration.