Rubidium traced etalon wavelength calibrators: Towards deployment at observatories

Christian Schwab*, Tobias Feger, Julian Stürmer, Andreas Seifahrt, Yulia V. Gurevich, Dmytro Rogozin, Thorsten Führer, Samuel P. Halverson, Ryan C. Terrien, Thomas Legero, David W. Coutts, Gert Raskin, Thomas Walther, Jacob L. Bean, Andreas Quirrenbach

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference proceeding contributionpeer-review

5 Citations (Scopus)
116 Downloads (Pure)


Precise wavelength calibration is a persistent problem for highest precision Doppler spectroscopy. The ideal calibrator provides an extremely stable spectrum of equidistant, narrow lines over a wide bandwidth, is reliable over timescales of years, and is simple to operate. Unlike traditional hollow cathode lamps, etalons provide an engineered spectrum with adjustable line distance and width and can cover a very broad spectral bandwidth. We have shown that laser locked etalons provide the necessary stability with an ideal spectral format for calibrating precision Echelle spectrographs, in a cost-effective and robust package. Anchoring the etalon spectrum to a very precisely known hyperfine transition of rubidium delivers cm/s-level stability over timescales of years. We have engineered a fieldable system which is currently being constructed as calibrator for the MAROON-X, HERMES, KPF, FIES and iLocater spectrographs.

Original languageEnglish
Title of host publicationGround-based and Airborne Instrumentation for Astronomy VII
EditorsChristopher J. Evans, Luc Simard, Hideki Takami
Place of PublicationBellingham, Washington
Number of pages7
ISBN (Electronic)9781510619586
ISBN (Print)9781510619579
Publication statusPublished - 9 Jul 2018
EventGround-based and Airborne Instrumentation for Astronomy VII 2018 - Austin, United States
Duration: 10 Jun 201814 Jun 2018

Publication series

NameProceedings of SPIE
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceGround-based and Airborne Instrumentation for Astronomy VII 2018
Country/TerritoryUnited States

Bibliographical note

Copyright 2018 Society of Photo-Optical Instrumentation Engineers (SPIE). One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.


  • Doppler technique
  • Echelle spectrograph
  • exoplanets
  • Fabry-Perot
  • high-resolution spectroscopy
  • radial velocity
  • stabilized etalon
  • wavelength calibration


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