Imaging & Spectroscopy

Calibration Unit Design for High-Resolution Infrared Spectrograph for Exoplanet Characterization (HISPEC)

By Keith Cowing
Status Report
November 20, 2023
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Calibration Unit Design for High-Resolution Infrared Spectrograph for Exoplanet Characterization (HISPEC)
Top-Down view of the HISPEC RSPEC Spectrograph including the integrating sphere and flat-fielding light path — astro-ph.EP

The latest generation of high-resolution spectrograph instruments on 10m-class telescopes continue to pursue challenging science cases. Consequently, ever more precise calibration methods are necessary to enable trail-blazing science methodology.

We present the High-resolution Infrared SPectrograph for Exoplanet Characterization (HISPEC) Calibration Unit (CAL), designed to facilitate challenging science cases such as Doppler imaging of exoplanet atmospheres, precision radial velocity, and high-contrast high-resolution spectroscopy of nearby exoplanets. CAL builds upon the heritage from the pathfinder instrument Keck Planet Imager and Characterizer (KPIC) and utilizes four near-infrared (NIR) light sources encoded with wavelength information that are coupled into single-mode fibers.

They can be used synchronously during science observations or asynchronously during daytime calibrations. A hollow cathode lamp (HCL) and a series of gas absorption cells provide absolute calibration from 0.98 {\mu}m to 2.5 {\mu}m. A laser frequency comb (LFC) provides stable, time-independent wavelength information during observation and CAL implements a lower finesse astro-etalon as a backup for the LFC. Design lessons from instrumentation like HISPEC will serve to inform the requirements for similar instruments for the ELTs in the future.

Ben Sappey, Quinn Konopacky, Nemanja Jovanovic, Ashley Baker, Jerome Maire, Samuel Halverson, Dimitri Mawet, Jean-Baptiste Ruffio, Rob Bertz, Michael Fitzgerald, Charles Beichman, Garreth Ruane, Marc Kassis, Chris Johnson, Ken Magnone, HISPEC Team

Comments: 16 pages, 14 figures
Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
Cite as: arXiv:2311.10239 [astro-ph.IM] (or arXiv:2311.10239v1 [astro-ph.IM] for this version)
Submission history
From: Ben Sappey
[v1] Fri, 17 Nov 2023 00:00:26 UTC (11,863 KB)

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻