Shear PSF Calibration Parameters¶

Data product name¶

shePsfCalibrationParameters

Data product custodian¶

SHE

Data model tag¶

8.0

Name of the Schema file¶

ST_DM_Schema/dictionary/pro/she/euc-test-she.xsd

Schema documentation tag¶

Documentation for data product element shePsfCalibrationParameters:

This product contains the parameters for the Shear PSF Calibration.

Documentation for data product element Header:

The generic header of the product.

Data product elements¶

DataStorage (shePsfCalibrationParametersFile)

DataContainer (dss:dataContainer)

Processing Element(s) creating/using the data product¶

SHE

Processing function using the data product¶

SHE

Detailed description of the data product¶

PSF Calibration parameters, giving the current state of the telescope for parameters which are expected to vary over the lifetime of the mission. Format TBD

Will include a set of Zernike amplitude/telescope optical layout parameters which describe wavefront propagation through the system, expected to consist of < 100 params (floats).

Surface errors defined as a map of free pixelised values, sampled across the field-of-view. Expected size ~ 30x30 floats per FOV, with ~400 FOV positions (details TBD).

Detector state format TBD, will include parameters describing the brighter-fatter effect, chip-to-chip variation.

Will contain parameters decribing the FOV-dependent mapping between the telescope model (optical layout) and zernike amplitudes, as a list of coeeficients to a polynomial fit. TBD.

Will include catalogue of star identifier with \chi^2 value per star, to satisfy R-SHE-PRD-F-100, as well as sub-pixel stellar position on the detector (2 floats), for the stellar images used in the calibration

CTI residual parameterisation TBD

Output File¶

The FITS output file will contain the following information:

HDU List

Telescope Mode parameters
Zernike Mode Parameters
Surface Error Parameters
Detector Model Parameters
Other model parameters
Telescope Model Parameters
Diagnostics

Primary Header¶

The primary head will contain the following additional information:

Time Stamp: Indentifies the date and time of fit.

Telescope Mode parameters¶

Currently 19 telescope model parameters are considered:

TCON: Change in conicity
TRAD: Perturbations on radius of element
TFRN: FOM1,2,3 only. Flatness of mirror
TX: Translation in X (plane of exit pupil)
TY: Translation in Y (plane of exit pupil)
TZ: Translation in Z
RX: Rotation in X
RY: Rotation in Y

The catalogue will contain the following columns

Parameter name	Element	Type
SHE_PSF_CAL_M1TRAD	M1	Radial
SHE_PSF_CAL_M2TRAD	M2	Radial
SHE_PSF_CAL_FOM1TFRN	FOM1	Flatness
SHE_PSF_CAL_FOM2TFRN	FOM2	Flatness
SHE_PSF_CAL_M3TRAD	M3	Radial
SHE_PSF_CAL_DIC_TFRN	Dichroic	Flatness
SHE_PSF_CAL_M1TCON	M1	Conicity
SHE_PSF_CAL_M2TCON	M2	Conicity
SHE_PSF_CAL_M3TCON	M3	Conicity
SHE_PSF_CAL_M2TZ	M2	Translation Z
SHE_PSF_CAL_M2TX	M2	Translation X
SHE_PSF_CAL_M2TY	M2	Translation Y
SHE_PSF_CAL_M2RX	M2	Rotation X
SHE_PSF_CAL_M2RY	M2	Rotation Y
SHE_PSF_CAL_M3TZ	M3	Translation Z
SHE_PSF_CAL_M3TX	M3	Translation X
SHE_PSF_CAL_M3TY	M3	Translation Y
SHE_PSF_CAL_M3RX	M3	Rotation X
SHE_PSF_CAL_M3RY	M3	Rotation Y

Zernike Mode Parameters¶

Zernike fit parameters refer to Zernike Polynomial amplitudes themselves. The fits catalogue will contain the following columns:

SHE_PSF_CAL_FOVRNGX: Region of fit on the field of view in X
SHE_PSF_CAL_FOVRNGY: Region of fit on the field of view in Y
SHE_PSF_CAL_ZNKPLYAMP: List of Zernike Polynomial amplitudes

Surface Error Parameters¶

Surface error is parameterised as a gridded free variation in optical path difference on the exit pupil, and format TBF. The catalogue is expected to contain the following columns

FOV range X: Region of fit on the field of view in X
FOV range Y: Region of fit on the field of view in Y
Free OPD: 2D array image of additional free contribution to optical mode path difference on exit pupil. Size TBD.

Detector Model Parameters¶

The detector model parameterisation is TBD. Will include Brighter-Fatter effect parameterisation, CTI residual parameterisation, chip-to-chip variation.

Other model parameters¶

Other parameterisation may include parameterisation of the AOCS guiding and shutter speed models. Format TBD.

Telescope Model Parameters¶

The telescope model describes the relation between the telescope mode parameters and Zernike amplitudes across the field-of-view (links telescope mode and zernike mode parameters). Will consist of N coefficients describing a polynomial fit to Zernike amplitudes across the FOV. Format TBD.

Diagnostics¶

Diagnostics includes information used to verify the quality of the fit on a per-training object basis. The catalogue form is TBF, but is expected to contain a list of stellar object identifiers, as well as \chi^2 for each.