Flexure analysis with the X-shooter Physical Model
description
Transcript of Flexure analysis with the X-shooter Physical Model
Paul Bristow (ESO Instrumentation)
Thanks to:Andrea Modigliani, Joël Vernet & Florian Kerber, Sabine Moehler (ESO)Paolo Goldoni, Frédéric Royer & Régis Haigron (APC-SAp/CEA)
Follow the Photons – Edinburgh – October 2011
Paul Bristow (ESO Instrumentation)
Thanks to:Andrea Modigliani, Joël Vernet & Florian Kerber, Sabine Moehler (ESO)Paolo Goldoni, Frédéric Royer & Régis Haigron (APC-SAp/CEA)
Follow the Photons – Edinburgh – October 2011
Matrix Representation of Optics
Matrix Representation of Optics
ME is the matrix representation of the order m transformation performed by an Echelle grating with E at off-blaze angle . This operates on a 4D vector with components (wavelength, x, y, z).
ME is the matrix representation of the order m transformation performed by an Echelle grating with E at off-blaze angle . This operates on a 4D vector with components (wavelength, x, y, z).
ApplicationsApplications
Wavelength calibrationSimulations
Early DRS developmentEffects of modifications/upgrades
Instrument monitoring/QCAdvanced ETC?
Wavelength calibrationSimulations
Early DRS developmentEffects of modifications/upgrades
Instrument monitoring/QCAdvanced ETC?
Some backgroundSome background M. Rosa: Predictive calibration strategies: The
FOS as a case study (1995) P. Ballester, M. Rosa: Modeling echelle
spectrographs (A&AS 126, 563, 1997) P. Ballester, M. Rosa: Instrument Modelling in
Observational Astronomy (ADASS XIII, 2004) Bristow, Kerber, Rosa: four papers in HST
Calibration Workshop, 2006 UVES, SINFONI, FOS, STIS, CRIRES,
X-shooter – Bristow et al (Experimental Astronomy 31, 131, 2011)
M. Rosa: Predictive calibration strategies: The FOS as a case study (1995)
P. Ballester, M. Rosa: Modeling echelle spectrographs (A&AS 126, 563, 1997)
P. Ballester, M. Rosa: Instrument Modelling in Observational Astronomy (ADASS XIII, 2004)
Bristow, Kerber, Rosa: four papers in HST Calibration Workshop, 2006
UVES, SINFONI, FOS, STIS, CRIRES,X-shooter – Bristow et al (Experimental Astronomy 31, 131, 2011)
X-Shooter (300nm-2.5m)X-Shooter (300nm-2.5m)Commissioned 2009Vernet et al. 2011.
A & A. in pressModel for UVB, VIS
& NIR armsSame model kernelIndependent
configuration filesCross dispersed, medium res’n, single slitSingle mode (no moving components)Cassegrain & heavy => Flexure
Commissioned 2009Vernet et al. 2011.
A & A. in pressModel for UVB, VIS
& NIR armsSame model kernelIndependent
configuration filesCross dispersed, medium res’n, single slitSingle mode (no moving components)Cassegrain & heavy => Flexure
NIR Th-Ar HCL full slit
Solar like stellar point source and sky
X-shooter Flexure
X-shooter Flexure
Backbone flexureCauses movement of target on
spectrograph slitsCorrected with Automatic
Flexure Compensation exposures
Spectrograph flexureFlexing of spectrograph optical
benchCan also be measured in AFC
exposuresFirst order translation
automatically removed by pipeline
Backbone flexureCauses movement of target on
spectrograph slitsCorrected with Automatic
Flexure Compensation exposures
Spectrograph flexureFlexing of spectrograph optical
benchCan also be measured in AFC
exposuresFirst order translation
automatically removed by pipeline
VIS
UVB
NIR
Lab MeasurementsLab Measurements• NIR arm• Multi-pinhole• Translational & higher order distortions
AFC ExposuresAFC Exposures• Obtained with every science obs =>
large dataset ~300 exp from Jan – May 2011
• Single pinhole, Pen-ray lamp• Window:
• 1000x1000 win (UVB 12/VIS 14 lines)• Entire array (NIR 160 lines)
NIR UVB
VIS
Physical Model OptimisationPhysical Model Optimisation
FOR EVERY CALIBRATION EXPOSURE
Choosing “open” parametersChoosing “open” parametersAll parameters open
SlowOptimal resultDegeneracy
Physically motivated:Related to flexureConstrained by data
In these results:Prism orientation; Grating Orientation; Grating
constant; Camera focal length; Detector position and orientation
All parameters openSlowOptimal resultDegeneracy
Physically motivated:Related to flexureConstrained by data
In these results:Prism orientation; Grating Orientation; Grating
constant; Camera focal length; Detector position and orientation
NIRNIR
NIRNIR
NIRNIR
NIRNIR
(Product moment correlation)
VISVIS
VISVIS
VISVIS
UVBUVB
UVBUVB
UVBUVB
SummarySummary
Simple physical modelling approach:wavelength calibration for a number of
instrumentsRaw data simulationInstrument monitoring
Application to X-shooterFlexure monitoring
Allows identification of physical model parameters that correlate with instrument orientation
Simple physical modelling approach:wavelength calibration for a number of
instrumentsRaw data simulationInstrument monitoring
Application to X-shooterFlexure monitoring
Allows identification of physical model parameters that correlate with instrument orientation
Physical Model OptimisationPhysical Model Optimisation
QC Data9 pinhole mask, arc lamp:
Th-Ar (UVB 250 lines x 9 & VIS 390 lines x 9)pen-ray (NIR 140 lines x 9)
Daytime, Zenith (no flexure except hysteresis)1/week => small data setAutomatically processed by pipeline (ESO QC)
QC Data9 pinhole mask, arc lamp:
Th-Ar (UVB 250 lines x 9 & VIS 390 lines x 9)pen-ray (NIR 140 lines x 9)
Daytime, Zenith (no flexure except hysteresis)1/week => small data setAutomatically processed by pipeline (ESO QC)
Effe
ctiv
e ca
mer
a fo
cal l
engt
h (m
m)
Effe
ctiv
e ca
mer
a fo
cal l
engt
h (m
m)
UVB Camera temperature sensor reading (°C) VIS Camera temperature sensor reading (°C)
Det
ecto
r tip
(°)
Det
ecto
r til
t (°)
Eff
ectiv
e ca
mer
afo
cal l
engt
h (m
m)
Modified Julian Date (days)
Explain “our Physical Models” Compare to poly Uses
Calibration Simulation
Test DRS Investigate modifications/upgrades
Monitor/understand instrument behaviour History (Ballester & Rosa)
Introduce X-shooter Overview Flexure
Lab plots AFC Calibration exposures
Flexure Procedure Optimisation for 1 exposure Apply to all data Choosing open parameters
Flexure Results NIR
Residuals Sin plot Linear plots Table – highlight interesting param combinations
UVB Residuals Linear plots table
VIS Residuals Linear plots table
Flexure conclusions QC
Procedure Results
Summary
Explain “our Physical Models” Compare to poly Uses
Calibration Simulation
Test DRS Investigate modifications/upgrades
Monitor/understand instrument behaviour History (Ballester & Rosa)
Introduce X-shooter Overview Flexure
Lab plots AFC Calibration exposures
Flexure Procedure Optimisation for 1 exposure Apply to all data Choosing open parameters
Flexure Results NIR
Residuals Sin plot Linear plots Table – highlight interesting param combinations
UVB Residuals Linear plots table
VIS Residuals Linear plots table
Flexure conclusions QC
Procedure Results
Summary