Two Fabry-Perots and Two Calibration Units for CARMENES
The wavelength calibration and nightly drift measurements for CARMENES (Calar Alto high-Resolution search for M dwarfs with Exoearths with Near-infrared and optical Echelle Spectrographs) are provided by a combination of hollow cathode lamps and two Fabry-Pérot units.
CARMENES consists of two spectrograph, one for the visible part of the spectrum (520-960nm) and one for the near infrared (960-1710nm). Each spectrograph has its own calibration unit and its own Fabry-Pérot.
The calibration units are equipped with Th-Ne, U-Ar and U-Ne hollow cathode lamps as well as a flat field lamp. The Fabry-Pérots are optimized for the wavelength ranges of the spectrographs and use halogen-tungsten lamps as light sources.
The Fabry-Pérots have a free spectral range of 15GHz for the visible and 12.2GHz for the near infrared which translates to ∼17,900 useful emission lines for the visible spectrograph and ∼9,700 for the infrared. These lines are used to compute the wavelength solution, and to monitor the instrumental drift during the night.
The Fabry-Pérot units are temperature and pressure stabilized and designed to reach an internal stability of better than 10cm/s per night. Here, we present the designs of both Fabry-Pérot units and the calibration units.
Sebastian Schafer, Eike W. Günther, Ansgar Reiners, Johannes Winkler, Michael Pluto, Jörg SchillerSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
Cite as: arXiv:2606.05782 [astro-ph.IM](or arXiv:2606.05782v1 [astro-ph.IM] for this version)
https://doi.org/10.48550/arXiv.2606.05782
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Journal reference: Proc. SPIE 10702, Ground-based and Airborne Instrumentation for Astronomy VII, 1070276 (9 Jul 2018)
Related DOI:
https://doi.org/10.1117/12.2315241
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Submission history
From: Sebastian Schäfer
[v1] Thu, 4 Jun 2026 07:09:56 UTC (7,925 KB)
https://arxiv.org/abs/2606.05782
Astrobiology,
