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Proceedings Paper

Model-based wavelength calibration for CRIRES
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Paper Abstract

CRIRES, a first generation VLT instrument, is a cryogenic high-resolution (R~100,000) IR spectrograph operating in the range 1-5 μm. Here we present a model based wavelength calibration for CRIRES. The procedure uses a streamlined model of the CRIRES optical path that enables calculation of the location of the illumination in the detector focal plane at sub-pixel accuracy for a given wavelength and instrumental configuration. The instrumental configuration is described in terms of the tips and tilts of optical surfaces, their optical properties and environmental conditions. These parameters are derived through the application of a minimisation algorithm that is capable of using multiple realisations of the model to find the configuration which results in the optimal match between simulated wavelength data and dedicated calibration exposures. Once the configuration is accurately determined the model can be used to provide the dispersion solution for science exposures or to produce two dimensional simulated data for a given spectral source. In addition we describe comparisons to early laboratory data and the optimisation strategy adopted.

Paper Details

Date Published: 30 June 2006
PDF: 10 pages
Proc. SPIE 6270, Observatory Operations: Strategies, Processes, and Systems, 62701T (30 June 2006); doi: 10.1117/12.670785
Show Author Affiliations
Paul Bristow, European Southern Observatory (Germany)
Florian Kerber, European Southern Observatory (Germany)
Michael R. Rosa, European Southern Observatory (Germany)
Jean Francois Pirard, European Southern Observatory (Germany)
Ralf Siebenmorgen, European Southern Observatory (Germany)
Hans-Ulrich Käufl, European Southern Observatory (Germany)


Published in SPIE Proceedings Vol. 6270:
Observatory Operations: Strategies, Processes, and Systems
David R. Silva; Rodger E. Doxsey, Editor(s)

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