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JWST's WFSC NIRCam Fine Phasing Template, available in the Astronomer’s Proposal Tool (APT), is used for fine phasing and LOS jitter monitoring. 

Introduction

In WFSC NIRCam Fine Phasing the user may select two different types of activities. The user may both select Line-Of-Sight (LOS) jitter monitoring and Fine Phasing in a single visit, or either type may be selected separately. In monitoring situations, both LOS and Fine Phasing would be selected. A visit would start with a Target Acquisition to place the selected target in the center of a 64 x 64 subarray. Next, a series of 8 x 8 subarray images will be taken (center 8x8 pixels of the TA subarray). Lastly, the Fine Phasing activities would be executed. No additional Target Acquisition is needed for the Fine Phasing activities.

Note that there is an implicit 2-point dither with these observations. See Table F2.11 (link).

The WFSC NIRCam Fine Phasing Template consists of the following parameters:

FieldDetailsValues Notes
General Information   
Observation Number assign observation number

number


  Observation Labelprovide observation labeltextoptional
Observations Commentsprovide observation commentstextoptional
 Target Nameselect Target Namechoose from listfrom Target List
 Special Requirementsspecify special requirementschoose from listif needed
Template Specific Information   
Sensing Type
select Sensing TypeChoose from list 
 Moduleselect ModuleA, B 
LOS Jitter Information (if SENSING TYPE = LOS JITTER or BOTH)
Acquisition Targetselect Target Namechoose from listfrom Target List
Acquisition Subarray

based on selection of Module

Acquisition Filterdefault value

F212N

Long Wave pupil is in the FLAT (opaque) position.

Acquisition Readout Pattern

default valueRAPID
Acquisition Number of Groups/Integrationselect number of groups/integrationchoose from list
Acquisition Number of Integrations/Exposuredefault value1
LOS Subarray

based on selection of Module
LOS Images Filtersdefault valueF200WLong Wave pupil is in the FLAT (opaque) position.
LOS Images Readout Patterndefault valueRAPID
LOS Images Number of Groups/Integrationspecify number of groups/integration1 - 1000
LOS Images Number of Integrations/Exposurespecify number of integrations/exposure1 - 65535
WESC Fine Phasing Information (if SENSING TYPE = FINE PHASING)
Diversityselect diversitychoose from list 

Plus/Minus 8 Waves Defocus (F212N) Imaging Parameters Information

Filters
see table
Readout Patternselect readout patternRAPID, BRIGHT1
Number of Groups/Integrationspecify number of groups/integrationnumber
Number of Integrations/Exposurespecify number of integrations/exposurenumber

Plus 12 Waves Defocus Imaging Parameters Information

Filters
see table.
Readout Pattern

select readout pattern

RAPID, BRIGHT1
Number of Groups/Integrationspecify number of groups/integrationnumber
Number of Integrations/Exposurespecify number of integrations/exposurenumber

 Plus/Minus 4 Waves Defocus Imaging Parameters Information

Filters
see table
Readout Patternselect readout patternRAPID, BRIGHT1
Number of Groups/Integrationspecify number of groups/integrationnumber
Number of Integrations/Exposurespecify number of integrations/exposurenumber

 Plus/Minus 8 Waves Defocus (F187N) Imaging Parameters Information

Filters
see table
Readout Patternselect readout patternRAPID, BRIGHT1
Number of Groups/Integrationspecify number of groups/integrationnumber
Number of Integrations/Exposurespecify number of integrations/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,  and Special Requirements. 

Target Name

Select the TARGET NAME [TBD] from the list of targets previously entered (see list of targets).

Sensing Type

SENSING TYPE = FINE PHASING, LOS JITTER, BOTH

This parameter specifies the type of sensing observation to be executed.

Note for developer: For SENSING TYPE=BOTH or LOS JITTER, do not allow user to select Special Requirement WAVEFRONT SENSING with a value of SENSING_CONTROL, since the resulting visit file will not contain the on-board script for wavefront control commanding. Also, do not duplicate the exposures when SENSING TYPE=BOTH.

Module

MODULE [ MODULE] = A, B

This parameter specifies the module to be used to obtain the data.

WFSC LOS Jitter Monitoring

If SENSING TYPE = LOS JITTER or BOTH, a target acquisition is performed to place the target star in the center of a 64x64 subarray. The center 8x8 pixels will be used for a series of NIRCam images.

Target Acquisition

The following parameters are used to define the Target Acquisition.

Acquisition Target

Select the TARGET NAME [TACQ TARGET] from the list of targets previously entered.  

Acquisition Subarray

SUBARRAY = SUB64FP1A, SUB64FP1B
This parameter specifies the subarray used for acquisition images, and is SUB64FP1A for Module A and SUB64FP1B for Module B.

Acquisition Filter

The Target Acquisition FILTER is F212N. Note that the Long Wave pupil will be in the FLAT (opaque) position.

Acquisition Readout Pattern

The READOUT PATTERN [TACQ PATTERN] for target acquisition is RAPID.

Acquisition Number of Groups/Integration

NUMBER OF GROUPS/INTEGRATION [TACQ NGROUPS] = 3, 5, 9, 17, 33, 65

This parameter specifies the number of groups in an integration.

Acquisition Number of Integrations/Exposure

NUMBER OF INTEGRATIONS/EXPOSURE specifies the number of times the integration is repeated, and is always 1.

 LOS Subarray

SUBARRAY [SUBARRAY] = SUB8FP1A, SUB8FP1B

This parameter specifies the subarray used for LOS jitter images, and is SUB8FP1A for Module A,and SUB8FP1B for Module B.

 LOS Images Filters

The FILTER [FILTSHORT] for LOS Jitter is F200W. Note that the Long Wave pupil will be in the FLAT (opaque) position.

 LOS Images Readout Pattern

The READOUT PATTERN [PATTERN] for LOS Jitter is RAPID.

  LOS Images Number of Groups/Integration

NUMBER OF GROUPS/INTEGRATION [NGROUPS] = 1 - 1000

This parameter specifies the number of groups in an integration.

 LOS Number of Integrations/Exposure

NUMBER OF INTEGRATIONS/EXPOSURE [NINTS] = 1 - 65535

This parameter specifies the number of times the integration is repeated.

WFSC Fine Phasing

WFSC Fine Phasing will be executed several times during commissioning to measure OTE wavefront errors. It will also be executed approximately every 2 days during the mission to measure and optionally correct the wavefront error. Fine Phasing measurements consist of a series of steps that collect NIRCam images of a star using the Weak Lenses. Each step within the series consists of two exposures separated by a small (few pixel) dither. There are four types of exposures: Plus/Minus 8 Wave Defocus (F212N), Plus 12 Waves Defocus, Plus/Minus 4 Waves Defocus, and Plus/Minus 8 Waves Defocus (F187N). All the exposures of a given type use the same exposure parameters. The parameter DIVERSITY allows the user to select the types of exposures.

If a wavefront correction is required, then a Wavefront Control File containing one mirror control group should be uploaded prior to the execution of the observation.

A Wavefront Control File (provided by the WFSC Scientist) may be attached to each visit by the PPS Operator.

In addition to the following template parameters, this template will require a value be specified for the Special Requirement WAVEFRONT SENSING.

Note that this type of observation cannot be obtained with other parallel observations or as a parallel to normal science observations.

 Diversity

DIVERSITY [DIVERSITY] = ALL, ALL+187N, PM8

This parameter specifies the type of focus diversity images to obtain.

If ALL is specified, images with +8, -8, +12, -4, and +4 waves defocus (a total of 10 exposures) are obtained. These +8 and -8 waves defocused images use the F212N filter.

If ALL+187N is specified, the images described above are obtained, with the addition of images with +8 and -8 waves defocus using the F187N filter (a total of 14 exposures).

If PM8 (Plus and Minus 8 waves) is specified, only the +8 and -8 waves defocus images (using F212N) are obtained (a total of 4 exposures). Note that each step results in two exposures being obtained.

 Plus/Minus 8 Waves Defocus (F212N) Imaging Parameters

Filters

The following filters will be used to obtain the data.

Plus/Minus 8 waves defocus with F212N (DIVERSITY=ALL, ALL+187N, PM8)
Step number
SW PupilSW FilterLW PupilLW FilterSubarray

1 (-8 defocus)

WLM8

F212N

F405N

F444W

FULL

2 (+8 defocus)

WLP8

F212N

F405N

F444W

FULL

Readout Pattern

READOUT PATTERN [READOUT PATTERN] = RAPID, BRIGHT1

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. (warning)The range is 1-10.

 Number of Integrations/Exposure

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

   Plus 12 Waves Defocus Imaging Parameters

Filters

The following filters will be used.

Plus 12 waves defocus (DIVERSITY=ALL, all+187N)
Step numberSW PupilSW FilterLW PupilLW FilterSubarray

3 (+12 defocus)WLP8WLP4F405NF444WFULL

Readout Pattern

READOUT PATTERN [READOUT PATTERN] = RAPID, BRIGHT1

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.

Number of Integrations/Exposure

NUMBER OF INTEGRATIONS/EXPOSURE [NINTS] field specifies the number of times the integration is repeated.

Plus/Minus 4 Waves Defocus Imaging Parameters

Filters

The following filters will be used.

Plus/Minus 4 waves defocus (DIVERSITY=ALL, ALL+187N)
Step numberSW PupilSW FilterLW PupilLW FilterSubarray

4 (-4 defocus)

WLM8

WLP4

F405N

F444W

FULL

5 (+4 defocus)

CLEAR

WLP4

F405N

F444W

FULL

Readout Pattern

READOUT PATTERN [READOUT PATTERN] = RAPID, BRIGHT

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.

Number of Integrations/Exposure

NUMBER OF INTEGRATIONS/EXPOSURE [NINTS] field specifies the number of times the integration is repeated.

 Plus/Minus 8 Waves Defocus (F187N) Imaging Parameters

Filters

The following filters will be used.

Plus/Minus 8 waves defocus with F187N (DIVERSITY=ALL+187N)
Step numberSW
Pupil
SW FilterLW
Pupil
LW
Filter
Subarray

6 (-8 defocus)

WLM8

F187N

F405N

F444W

FULL

7 (+8 defocus)

WLP8

F187N

F405N

F444W

FULL

Readout Pattern

READOUT PATTERN [READOUT PATTERN] = RAPID, BRIGHT1

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.

Number of Integrations/Exposure

NUMBER OF INTEGRATIONS/EXPOSURE [NINTS] field specifies the number of times the integration is repeated.

Change log

 Click here to expand...

Version 3 (April 19, 2019)

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


Version 2 (August 24, 2017)

  1. PR 87834 - add developer note to Sensing Type parameter


Version 1 (May 30, 2017)

  1. This is the converted Word File from Chapter 60.
  2. PR 87783 - revised TA NGroups
  3. PR 87895 - revised names of Number of Groups and Integrations

Keywords

JWST WFSC NIRCam Fine Phasing template

JWST WFSC NIRCam Fine Phasing 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.

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