Flexure analysis with the Xshooter Physical Model Paul

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Flexure analysis with the X-shooter Physical Model Paul Bristow (ESO Instrumentation) Thanks to: Andrea

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

Matrix Representation of Optics ME is the matrix representation of the order m transformation

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 4 D vector with components (wavelength, x, y, z).

Applications Wavelength calibration Simulations Early DRS development Effects of modifications/upgrades Instrument monitoring/QC Advanced ETC?

Applications Wavelength calibration Simulations Early DRS development Effects of modifications/upgrades Instrument monitoring/QC Advanced ETC?

Some background M. Rosa: Predictive calibration strategies: The FOS as a case study (1995)

Some 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)

X-Shooter (300 nm-2. 5 m) Commissioned 2009 Vernet et al. 2011. A & A.

X-Shooter (300 nm-2. 5 m) Commissioned 2009 Vernet et al. 2011. A & A. in press Model for UVB, VIS & NIR arms Same model kernel Independent configuration files Cross dispersed, medium res’n, single slit Single mode (no moving components) Cassegrain & heavy => Flexure

NIR Th-Ar HCL full slit

NIR Th-Ar HCL full slit

Solar like stellar point source and sky

Solar like stellar point source and sky

X-shooter Flexure Backbone flexure Causes movement of target on spectrograph slits Corrected with Automatic

X-shooter Flexure Backbone flexure Causes movement of target on spectrograph slits Corrected with Automatic Flexure Compensation exposures Spectrograph flexure Flexing of spectrograph optical bench Can also be measured in AFC exposures First order translation automatically removed by pipeline UVB VIS NIR

Lab Measurements • NIR arm • Multi-pinhole • Translational & higher order distortions

Lab Measurements • NIR arm • Multi-pinhole • Translational & higher order distortions

AFC Exposures • Obtained with every science obs => large dataset ~300 exp from

AFC Exposures • Obtained with every science obs => large dataset ~300 exp from Jan – May 2011 • Single pinhole, Pen-ray lamp • Window: • 1000 x 1000 win (UVB 12/VIS 14 lines) • Entire array (NIR 160 lines) NIR UVB VIS

Physical Model Optimisation E R U S O N O I T A R

Physical Model Optimisation E R U S O N O I T A R B Y R E F R O EV I L CA P X E

Choosing “open” parameters All parameters open Slow Optimal result Degeneracy Physically motivated: Related to

Choosing “open” parameters All parameters open Slow Optimal result Degeneracy Physically motivated: Related to flexure Constrained by data In these results: Prism orientation; Grating Orientation; Grating constant; Camera focal length; Detector position and orientation

NIR

NIR

NIR

NIR

NIR

NIR

NIR (Product moment correlation)

NIR (Product moment correlation)

VIS

VIS

VIS

VIS

VIS

VIS

UVB

UVB

UVB

UVB

UVB

UVB

Summary Simple physical modelling approach: wavelength calibration for a number of instruments Raw data

Summary Simple physical modelling approach: wavelength calibration for a number of instruments Raw data simulation Instrument monitoring Application to X-shooter Flexure monitoring Allows identification of physical model parameters that correlate with instrument orientation

Physical Model Optimisation QC Data 9 pinhole mask, arc lamp: Th-Ar (UVB 250 lines

Physical Model Optimisation QC Data 9 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 set Automatically processed by pipeline (ESO QC)

Effective camera focal length (mm) UVB Camera temperature sensor reading (°C) VIS Camera temperature

Effective camera focal length (mm) UVB Camera temperature sensor reading (°C) VIS Camera temperature sensor reading (°C)

Modified Julian Date (days) Effective camera focal length (mm) Detector tip (°) Detector tilt

Modified Julian Date (days) Effective camera focal length (mm) Detector tip (°) Detector tilt (°)

 Explain “our Physical Models” Compare to poly Uses Calibration Simulation Test DRS Investigate

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