MIRI Coronagraphic Photometric Calibration Template Parameters
JWST's MIRI Coronagraphic Photometric Calibration Engineering template, available in the Astronomer’s Proposal Tool (APT), is used for calibration observations for the MIRI instrument.
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 Coronagraphic Photometric Calibration observation will use a 4-points-of-light strategy to improve sampling of the PSF in multiple locations on the detector. Those points are described in Table 1. At each of these points, a four-point Dither pattern will be executed.
Note to developer: CPC dithers are from the PRD file MiriImagingDithers.txt (link to PRD).
Table 1. Four Points of Light for Coronagraphic Photometric Calibration Observations
| Mask | X, Y Positions (arcsecs) | |||
|---|---|---|---|---|
1 | 2 | 3 | 4 | |
MASK1065 | -9.46, 7.26 | 4.29, 7.26 | 4.62, -6.27 | -9.68, -6.38 |
MASK1140 | -9.46, 7.26 | 4.29, 7.26 | 4.62, -6.27 | -9.68, -6.38 |
MASK1550 | -9.46, 7.26 | 4.29, 7.26 | 4.62, -6.27 | -9.68, -6.38 |
MASKLYOT | -10.12, 9.46 | 5.5, 9.35 | 5.61, -6.27 | -10.56, -5.61 |
Note for developers: This pattern will be implemented as a canned mosaic, and no further mosaic parameters should be allowed. 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 MIRI Coronagraphic Photometric Calibration Engineering 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 |
| Observations Comments | provide observation comments | text | optional |
| Mosaic Properties | specify mosaic parameters | number | if needed |
| Special Requirements | specify special requirements | choose from list | if needed |
| Template Specific Information | |||
select target name | choose from list | from Target list | |
| Science Exposures | |||
select subarray | choose from list | ||
select filter name(s) | choose from list | ||
select readout pattern | FAST | ||
| 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 coronagraphic calibration exposure at each dither position | number | |
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, Mosaic Properties, and Special Requirements.
Target Name
Select the TARGET NAME [TBD] from the list of targets previously entered (see list of targets).
Subarray
SUBARRAY [SUBARRAY] = MASK1550, MASK1140, MASK1065, MASKLYOT
This parameter specifies the region of the detector that is to be used.
For a single SUBARRAY observation, several filters are allowed. Table 2 shows the available FILTERs for the selected SUBARRAY.
Table 2. Filters allowed for Each Subarray
| Subarray | Filter |
|---|---|
MASK1065 | FND, F1000W, F1500W, F560W, F1065C |
MASK1140 | FND, F1000W, F1500W, F560W, F1140C |
MASK1550 | FND, F1000W, F1500W, F560W, F1550C |
MASKLYOT | FND, F1000W, F1500W, F560W, F2300C |
Exposure Specifications
For each exposure to be executed, specify the FILTER, READOUT PATTERN, NUMBER OF GROUPS/INTEGRATION, NUMBER OF INTEGRATIONS/EXPOSURE, and the NUMBER OF EXPOSURES/DITHER.
Filter(s)
Select the name of each FILTER [FILTER] (see Table 3) that you wish to use.
Table 3. Filters Available for MIRI Coronagraphic Photometric Calibrations
| Filter | Central Wavelength λ0 (mm) | Filter Bandpass Δλ (mm) | Maximum Number of Integrations |
|---|---|---|---|
F1000W | 10.0 | 2.0 | TBD |
F1500W | 15.0 | 3.0 | TBD |
F560W | 5.6 | 1.2 | TBD |
F2300C | 23.0 | 4.6 | TBD |
F1550C | 15.5 | 0.8 | TBD |
F1140C | 11.4 | 0.6 | TBD |
F1065C | 10.7 | 0.5 | TBD |
FND | 13 | 10 | TBD |
Readout Pattern
READOUT PATTERN [READOUT PATTERN] = FAST, FASTR1
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 an integration.
MIRI integration duration may not be greater than 2000 seconds. Integration time = (Frame time * NUMBER OF GROUPS/INTEGRATION). Frame time is a property of the selected READOUT PATTERN. For more information, see MIRI Detector Readout Overview.
Note to developer: Maximum MIRI integration duration is specified in the PRD as max_integration_duration_miri in the observing_limitations table.
Number of Integrations/Exposure
NUMBER OF INTEGRATIONS/EXPOSURE [NINTS] field specifies the number of times the integration is repeated.
Number of Exposures/Dither
NUMBER OF EXPOSURES/DITHER [NEXP] specifies the number of times the coronagraphic photometric calibration 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: For this template the NO PARALLEL special requirement is added when the template is created. However if the NO PARALLEL special requirement is removed by the user, do the following: If NUMBER OF EXPOSURES/DITHER > 1. provide the following form: " 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)."