Page tree

JWST's NIRISS External Calibration template, available in the Astronomer’s Proposal Tool (APT), is used for calibration observations for the NIRISS instrument.   

Introduction

The following parameters are used to define NIRISS external calibration observations. If this template will be used for Multi-Instrument Multi-Field (MIMF) observations, you must add the Special Requirement WAVEFRONT SENSING = SENSING_ONLY .

 The NIRISS External Calibration template consists of the following parameters: 

FieldDetailsValues Notes
General Information   
 Observation Numberassign observation number

number 


Observation Labelprovide observation labeltextoptional
Observations Commentsprovide observation commentstextoptional
 Mosaic Propertiesspecify mosaic parametersnumberif needed
Special Requirementsspecify special requirementschoose from listif needed
Template Specific Information   
Pointing Typeselect pointing typePARALLEL, PRIME
Target Acquisition Exposures

Target Name

select target name

choose from list


Acquisition Targetselect acquisition target choose from list 
Acquisition Filterdefault valueF480M
Acquisition Modeselect target acquisition mode choose from list
Acquisition Readout Patternselect readout patternNIS, NISRAPID
Acquisition Number of Groups/Integrationselect number of groups per integrationchoose from list
Dither Patterns
Dithersselect dither pattern type  choose from list 
Primary Dithersselect number of stepschoose from listRequired if AMI dither pattern type is selected
Subpixel Positionsselect number of positions choose from listRequired if AMI dither pattern type is selected
Image Dithersselect number of stepschoose from listRequired if Imaging dither pattern type is selected
Image Dithersselect number of steps Automatically supplied if MIMF dither pattern type is selected
Image Dithersselect number of steps  choose from list Required if WFSS dither pattern type is selected
Pattern Sizeselect pattern size SMALL, MEDIUM, LARGE Required if WFSS dither pattern type is selected
Science Exposures
Subarray select subarray choose from list
Apertureselect aperturechoose from list
Pupil Wheel select pupil wheel element choose from list 
Filter Wheel select filter wheel element choose from list 
Readout Pattern select readout pattern NIS, NISRAPID 
Number of Groups/Integration specify number of groups per integrationnumber 
Number of Integrations/Exposure specify number of integrations per exposurenumber 

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. (warning) If POINTING TYPE = PARALLEL, TARGET NAME = NONE. If POINTING TYPE = PRIME, NONE is not available.

Target Acquisition Parameters

Acquisition Target 

(warning) When POINTING TYPE=PARALLEL, the Target Acquisition options are not available.

If no target acquisition is needed or if an offset star is to be used for the target acquisition observation, select the ACQUISITION TARGET [TACQ TARGET] to be NONE, or from the list of targets previously entered, respectively.

Select the ACQUISITION TARGET [TACQ TARGET] from the list of targets previously entered. When the science target is a Solar System target, the acquisition target MUST be the science target. Or, if no target acquisition is needed, select ACQUISITION TARGET to be NONE.

Note for developers: If the acquisition target is different from the science target, APT should provide an error if the distance between the ACQ and Science targets is greater than the Visit splitting distance found in the PRD . Also, if there are multiple pointings within a visit, then the rules have to apply to the greatest separation between acq target and pointing within the visit.

Note for developers: If the observation target is a fixed target, remove solar system targets from the acquisition target options. If the observation target is a Solar system target, remove all options from the acquisition target list except for the observation target and NONE.

Acquisition Filter  

The Target Acquisition FILTER is F480M.

Acquisition Mode

ACQUISITION MODE [TACQ MODE] = SOSSBRIGHT, SOSSFAINT, AMIBRIGHT, AMIFAINT

This field specifies the target acquisition mode to be used to obtain the acquisition data for bright or faint targets for SOSS or AMI observations. The SOSSBRIGHT or AMIBRIGHT modes are to be selected for targets with M-band magnitudes in the range 3.0 ≤ M ≤ 8.5, while the SOSSFAINT or AMIFAINT modes should be selected for targets with 8.5 ≤ M ≤ 14.5.

(warning) The SOSSFAINT and SOSSBRIGHT ACQUISITION MODEs are only meant to be used if the SUBARRAY for the subsequent exposures is SUBSTRIP96, SUBSTRIP256, or SUBTASOSS.  The AMIFAINT and AMIBRIGHT ACQUISITION MODEs are only meant to be used if the SUBARRAY for the subsequent exposures is SUBTAAMI or SUB80. Other uses are not allowed because the science aperture is too far from the ACQUISITION TARGET the required slew would be greater than the visit splitting distance (see Guide star breaking distance table).

Note for developers: If SOSSBRIGHT or SOSSFAINT is selected, the TA subarray will be SUBTASOSS. If AMIBRIGHT or AMIFAINT is selected, the TA subarray will be SUBTAAMI.

Acquisition Readout Pattern

READOUT PATTERN [TACQ PATTERN] = NIS, NISRAPID

This field specifies the readout pattern to be used to obtain the acquisition data.

Note for developers: The NIS option is only available when TACQ MODE = AMIFAINT or SOSSFAINT.

Acquisition Number of Groups/Integration

NUMBER OF GROUPS/INTEGRATION [TACQ NGROUPS] = 3, 5, 7, 9, 11, 13, 15, 17, 19

This parameter specifies the number of groups in an integration.

Note that the NUMBER OF INTEGRATIONS/EXPOSURE is set to 1 for target acquisition observations.

Science Parameters

Pointing Type

POINTING TYPE  = PARALLEL, PRIME (default)

This parameter enables the user to control whether the data will be obtained in parallel like other calibrations, or as a primary observation like regular science.

Note for developers:

  • This field is not saved directly into the database.
  • If PRIME, make TARGET NAME required, remove the NONE option, and make the default "None Selected." If a PARALLEL special requirement is present, remove it.
  • If PARALLEL, set TARGET NAME = NONE (not changeable), set TACQ TARGET=NONE (not changeable), hide the target acquisition options, and set DITHER PATTERN TYPE = NONE. If a PARALLEL special requirement is not present, add it.

DITHER PATTERN TYPE [PATTERN TYPE] = NONE, AMI, IMAGING, MIMF, WFSS

This field specifies the science observation mode of the dither pattern. (warning) If POINTING TYPE = PARALLEL, the DITHER PATTERN TYPE options are not available.

None

This value indicates that no dithering will be performed.

AMI

This parameter is needed to specify an AMI dither. If this dither pattern type is selected, the following two parameters must be set:

Primary Dithers

PRIMARY DITHERS [PRIMARY DITHERS] = NONE, 2, 3, 4

This parameter indicates the number of steps in the primary dither.

Subpixel Positions

SUBPIXEL POSITIONS [SUBPIXEL POSITIONS] = NONE, 5, 9, 25

This parameter indicates the number of sub-pixel positions. These will be executed at each primary dither position.

Imaging

The following parameter is needed to specify the Imaging dither. If this dither pattern type is selected, the following parameter must be set.

Image Dithers

IMAGE DITHERS [IMAGE DITHERS] = 2, 3, 4

This parameter indicates the number of steps in the primary dither.

MIMF

The following parameter is needed to specify the MIMF dither. If this dither pattern type is selected, the following parameter will be set.

Image Dithers

IMAGE DITHERS [IMAGE DITHERS] = 2  

This parameter indicates the number of steps in the primary dither. Note that the value of 2 is fixed for MIMF dithers; no other value is available.

WFSS

The following parameter is needed to specify the WFSS dither. If this dither pattern type is selected, the following two parameters must be set:

Image Dithers

 IMAGE DITHERS [IMAGE DITHERS] = 2, 3, 4, 6, 8, 12, 16

This parameter indicates the number of steps in the primary dither.

Pattern Size

PATTERN SIZE [PATTERN SIZE] = SMALL, MEDIUM, LARGE

This parameter indicates the size of the dither.

The following parameters are used to define each external calibration exposure specification in an observation.

Subarray

SUBARRAY [SUBARRAY] = SUBTASOSS, SUBTAAMI, SUB64, SUB80, SUB128, SUB256, WFSS64R, WFSS64C, WFSS128R, WFSS128C, SUBSTRIP96, SUBSTRIP256, SUBAMPCAL, FULL

This parameter specifies the region of the SCA that is to be read out. See Table 1 for details.

Table 1. Subarrays for NIRISS External Calibration

Subarray

Size( cols x row)

Col corner

 Row corner

Frame read time (s)

SUBTASOSS

64 x 64

891

63

0.04550

SUBTAAMI

64 x 64

1905

932

0.04550

SUB64

64 x 64

1

1

0.04550

SUB80

80 x 80

1969

925

0.07452

SUB128

128 x 128

1

1

0.18060

SUB256

256 x 256

1

1

0.68876

WFSS64R

2048 x 64

1

1

0.34060

WFSS64C

64 x 2048

1

1

1.55724

WFSS128R

2048 x 128

1

1

0.67596

WFSS128C

128 x 2048

1

1

2.86860

SUBSTRIP96

96 x 2048

151

1

2.21292

SUBSTRIP256

256 x 2048

1

1

5.49132

SUBAMPCAL

1792 x 512

257

1537

9.25452

FULL

2048 x 2048

1

1

10.7368

Aperture

APERTURE = DEFAULT APERTURE,  (see Table 2 for parameter values)
This parameter specifies the aperture used for the observation. DEFAULT APERTURE specifies the aperture currently mapped to the selected SUBARRAY (mapping in Appendix H5).

Table 2. Apertures for NIRISS External Calibration

Apertures

NIS_AMI1       

NIS_FP4MIMF    

NIS_WFSS128    

NIS_AMI2       

NIS_FP5MIMF    

NIS_WFSS128C   

NIS_AMI3       

NIS_SOSSFULL   

NIS_WFSS128C3  

NIS_AMI4       

NIS_SOSSTA     

NIS_WFSS128R   

NIS_AMIFULL    

NIS_SUB128     

NIS_WFSS128R3  

NIS_AMITA      

NIS_SUB256     

NIS_WFSS64     

NIS_CEN        

NIS_SUB64      

NIS_WFSS64C    

NIS_CEN_OSS    

NIS_SUBAMPCAL  

NIS_WFSS64C3   

NIS_FP1MIMF    

NIS_SUBSTRIP256

NIS_WFSS64R    

NIS_FP2MIMF    

NIS_SUBSTRIP96 

NIS_WFSS64R3

NIS_FP3MIMF    

NIS_WFSS_OFFSET

NIS_WFSS128   

Pupil Wheel Elements

PUPIL WHEEL [PUPIL] = CLEARP, F090W, F115W, F140M, F150W, F158M, F200W, NRM, GR700XD

This parameter specifies the pupil wheel element to be used for the exposure specification.

Note for developers: Several of these optical elements in the pupil wheel are used as options for the FILTER field in other NIRISS templates.

Filter Wheel

FILTER WHEEL [FILTER] = CLEAR, GR150R, GR150C, F277W, F356W, F380M, F430M, F444W, F480M

This parameter specifies the filter wheel element to be used for the exposure specification. For each exposure specification, specify the name of the element in the filter wheel.

Note for developers: The GR150R and GR150C optical elements are (also) used as options for the GRISM field in the NIRISS WFSS template.

Readout Pattern

READOUT PATTERN [READOUT PATTERN] = NIS, NISRAPID

This field specifies the readout pattern to be used to obtain the science data. NIS is used for longer exposure durations and NISRAPID is used for shorter exposure durations.

Number of Groups/Integration

NUMBER OF GROUPS/INTEGRATION [NGROUPS] specifies the number of groups in an integration. (warning)For readout pattern NIS, the range is 1-200, while for NISRAPID the range is 1-800.

Number of Integrations/Exposure

NUMBER OF INTEGRATIONS/EXPOSURE [NINTS] field specifies the number of times the integration is repeated. (warning)The allowed range is 1-10,000.

Change log

 Click here to expand...

The initial version of this chapter was provided by Lily Liu. 


Version 10 (April 18, 2019)

  1. Editorial change (moved change log to main article).


Version 9  (December 20, 2018)

  1. PROPINSTJWST-91218 - updated developer note in Pointing Type section.


Version 8 (October 2, 2018)

  1. PR 86766 - added Aperture section.


Version 7 (July 23, 2018)

  1. PR 79707 - Added Pointing Type section, updated Acquisition Target and Dither section 


Version 6 (June 20, 2018)

  1. PR 89667 - Updated red note to Acquisition Target section regarding SOSS and AMI modes


Version 5 (December 26, 2017)

  1. PR 89483 - added restriction on Acq Target for SS observations


Version 4 (October 2, 2017)

  1. PR 87895 - updated Exposure field labels to Groups/Integration and Integrations/Exposure
  2. PR 87961 - updated TA Readout Pattern to include NIS


Version 3 (May 15, 2017)

  1. PR 87006 - updated Image dithers for WFSS


Version 2 (January 4, 2017)

  1. PR 85608 - removed statement about Acq Flux, and added new section to state default Acq Filter
  2. PR 85863 - updated developer note for Acquisition Target
  3. PR 85591 - updated Subpixel Positions values for AMI and updated Subarray information in Table1


Version 1 (October 28, 2016)

This is the converted Word file from Chapter 49

Keywords

JWST NIRISS External Calibration Template

JWST NIRISS External Calibration template parameters

Format definitions

Boldface italics type indicates the name of an APT parameter or a value for a parameter.

(warning)Red text indicates restrictions on a parameter.

Brown text indicates notes for the developers.

Green text indicates the name of the parameter used by Commanding.

On this page

JWST Proposal Parameters

Change log

Change log

  • No labels