Performance results of HESP physical model
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As a continuation to the published work on model based calibration technique with HESP(Hanle Echelle Spectrograph) as a case study, in this paper we present the performance results of the technique. We also describe how the open parameters were chosen in the model for optimization, the glass data accuracy and handling the discrepancies. It is observed through simulations that the discrepancies in glass data can be identified but not quantifiable. So having an accurate glass data is important which is possible to obtain from the glass manufacturers. The model’s performance in various aspects is presented using the ThAr calibration frames from HESP during its pre-shipment tests. Accuracy of model predictions and its wave length calibration comparison with conventional empirical fitting, the behaviour of open parameters in optimization, model’s ability to track instrumental drifts in the spectrum and the double fibres performance were discussed. It is observed that the optimized model is able to predict to a high accuracy the drifts in the spectrum from environmental fluctuations. It is also observed that the pattern in the spectral drifts across the 2D spectrum which vary from image to image is predictable with the optimized model. We will also discuss the possible science cases where the model can contribute.
KeywordsAstronomical spectrographs High spectral resolution Calibrations Instrument modelling Physical model based calibrations Simultaneous reference observations Double fibre Wave length calibrations Instrumental drifts
- 4.Mahadevan S., Ramsey L., Wright J., Endl M., Redman S., Bender C., Roy A., Zonak S., Troupe N., Engel L., Sigurdsson S., Wolszczan A., Zhao B.: The habitable zone planet finder: a proposed high-resolution NIR spectrograph for the Hobby Eberly Telescope to discover low-mass exoplanets around M dwarfs. Proc. SPIE 7735, Ground-based and Airborne Instrumentation for Astronomy III, 77356X (July 20, 2010); doi: 10.1117/12.857551
- 5.D‟Odorico S., Avila G. and Molaro P.: “More light through the fibre: an upgrading of the link 3.6-m – CES”. The Messenger No. 58 ESO, Dec. 1989Google Scholar
- 6.Kaufer A., Andersen J. and Pasquini L.: “FEROS, the fiber-fed extended range optical spectrograph for the ESO 1.52-m telescope”. The messenger No. 89. Sep 1989Google Scholar
- 7.Raskin G., van Winckel H., Hensberge H., Jorissen A., Lehmann H., Waelkens C., Avila G., de Cuyper J-P, Degroote P., Dubosson R., Dumortier L., Fr’emat Y., Laux U., Michaud B., Morren J., Perez Padilla J., Pessemier W., Prins S., Smolders K., van Eck S., and Winkler J.: HERMES: A high-resolution fibre-fed spectrograph for the Mercator telescope. Astron. Astrophys., 526:A69, February 2011Google Scholar