Wavelength calibration of a high resolution spectrograph with a partially stabilized 15-GHz astrocomb from 550-890 nm

Richard Alexander McCracken, Eric Depagne, Rudolf B. Kuhn, Nicolas Erasmus, Lisa A. Crause, Derryck Telford Reid

Research output: Contribution to journalArticle

21 Citations (Scopus)
102 Downloads (Pure)

Abstract

A visible astrocomb spanning 555–890 nm has been implemented on the 10-m Southern African Large Telescope, delivering complete calibration of one channel of its high-resolution spectrograph and an accurate determination of its resolving power. A novel co-coupling method allowed simultaneous observation of on-sky, Th-Ar lamp and astrocomb channels, reducing the wavelength calibration uncertainty by a factor of two compared to that obtained using only Th-Ar lines. The excellent passive stability of the master frequency comb laser enabled broadband astrocomb generation without the need for carrier-envelope offset frequency locking, and an atomically referenced narrow linewidth diode laser provided an absolute fiducial marker for wavelength calibration. The simple astrocomb architecture enabled routine operation by non-specialists in an actual telescope environment. On-sky spectroscopy results are presented with direct calibration achieved entirely using the astrocomb.
Original languageEnglish
Pages (from-to)6450-6460
Number of pages11
JournalOptics Express
Volume25
Issue number6
DOIs
Publication statusPublished - 13 Mar 2017

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