Paul Bristow (INSY/SED/ESO) Thanks to: Michael Rosa, Yves Jung, Florian Kerber, Andrea Modigliani, Sabine Moehler (ESO) Data Simulation Workshop – ESO Garching – April 2016 Paul Bristow (INSY/SED/ESO) Thanks to: Michael Rosa, Yves Jung, Florian Kerber, Andrea Modigliani, Sabine Moehler (ESO) Data Simulation Workshop – ESO Garching – April 2016 Physical Model Driven Calibration

 1999: Michael Rosa founded the Instrument Physical Modelling Group inside the Space Telescope – European Co-ordinating Facility  Florian Kerber, Anastasia Alexov (later Mauro Fiorentino) & Paul Bristow  ST-ECF was wound up in 2006  Legacy at ESO  Physical modelling and reference data for:  CRIRES  X-shooter  1999: Michael Rosa founded the Instrument Physical Modelling Group inside the Space Telescope – European Co-ordinating Facility  Florian Kerber, Anastasia Alexov (later Mauro Fiorentino) & Paul Bristow  ST-ECF was wound up in 2006  Legacy at ESO  Physical modelling and reference data for:  CRIRES  X-shooter Brief history of IPMG

 Projects included:  FOS  Wavelength scale (geomagnetic environment of HST)  Scattered light (grating analysis)  STIS  Wavelength calibration (discussed in detail below)  Simulated readout (CTE)  Reference data  HCL characterisation (spectral atlases, operational behaviour and ageing)  Material characterisation (e.g. refractive index data)  Recognised by a NASA group achievement award shared with NIST colleagues  Projects included:  FOS  Wavelength scale (geomagnetic environment of HST)  Scattered light (grating analysis)  STIS  Wavelength calibration (discussed in detail below)  Simulated readout (CTE)  Reference data  HCL characterisation (spectral atlases, operational behaviour and ageing)  Material characterisation (e.g. refractive index data)  Recognised by a NASA group achievement award shared with NIST colleagues Brief history of IPMG cont.

F. KerberPrecision Radial Velocity, PSU Astronet Roadmap 2009 “ As a core fundamental element, and as a guide, it is recommended that funding provision for laboratory astrophysics be included in the planning of all astronomical and space mission research programmes at a level of the order of 2% of overall budget, with each programme taking “ ownership ” and peer-review of this part of the project. ” Astronet Infrastructure Roadmap, p.132

F. KerberPrecision Radial Velocity, PSU Calibration Reference Data  Traceable to laboratory standards >> “ ground truth ”  For wavelength calibration reference data link to frequency/time  Meta Data describing “ what and how ”  Error information  Documented by original data provider  Published  Traceable to laboratory standards >> “ ground truth ”  For wavelength calibration reference data link to frequency/time  Meta Data describing “ what and how ”  Error information  Documented by original data provider  Published

Physical Model Based Wavelength Calibration

 M E 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). Matrix representation of optical components

Physical Model Optimisation

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

 Potentially more useful for CRIRES because of moving components  Never clear why it didn’t work properly  Erratic behaviour of the instrument did not help, but the problem was almost certainly with the model.  Potentially more useful for CRIRES because of moving components  Never clear why it didn’t work properly  Erratic behaviour of the instrument did not help, but the problem was almost certainly with the model. A Precautionary Note Regarding the CRIRES Implementation

X-Shooter (300nm-2.5m)  Commissioned 2009  Vernet et al 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  Commissioned 2009  Vernet et al 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

Solar like stellar point source and sky

Physical Model Optimisation FOR EVERY CALIBRATION EXPOSURE

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

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

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  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 VIS UVB NIR

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

AFC 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

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  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

(Product moment correlation)

VIS

Improvements and Updates  Full ray trace  computationally possible now  integration of eg. a Zemax library  Removes modelling assumptions (would be much easier to diagnose problems such as occurred for CRIRES)  No direct implementation in CPL  Despite fantastic support from Andrea and Yves…  It was still a huge overhead  Begin the development much earlier in the project lifetime  STIS: during operations  CRIRES: end of MAIT  X-Shooter: middle of MAIT  Ideal: During preliminary design phase  Full ray trace  computationally possible now  integration of eg. a Zemax library  Removes modelling assumptions (would be much easier to diagnose problems such as occurred for CRIRES)  No direct implementation in CPL  Despite fantastic support from Andrea and Yves…  It was still a huge overhead  Begin the development much earlier in the project lifetime  STIS: during operations  CRIRES: end of MAIT  X-Shooter: middle of MAIT  Ideal: During preliminary design phase

Summary  Model based calibration is not a new concept  It has been applied with some success to HST and ESO instruments  Needs to be supported by appropriate reference data  In 2016 this is computationally inexpensive while the development represents a small investment relative to EELT instrument resources  Model based calibration is not a new concept  It has been applied with some success to HST and ESO instruments  Needs to be supported by appropriate reference data  In 2016 this is computationally inexpensive while the development represents a small investment relative to EELT instrument resources