# Astro-comb calibrator and spectrograph characterization using a turn-key laser frequency comb

## TL;DR

This paper demonstrates the use of a turn-key laser frequency comb to calibrate an astrophysical spectrograph, achieving high stability and enabling precise radial velocity measurements, solar spectrum analysis, and CCD sensitivity studies.

## Contribution

It introduces a practical astro-comb system for spectrograph calibration, combining off-the-shelf components for high-precision astronomical measurements.

## Key findings

- Achieved 1 cm/s stability in spectrograph calibration
- Generated a 16 GHz, 90 nm bandwidth frequency comb
- Enabled detailed CCD sensitivity analysis

## Abstract

Using a turn-key Ti:sapphire femtosecond laser frequency comb, an off-the-shelf supercontinuum device, and Fabry-Perot mode filters, we report the generation of a 16 GHz frequency comb spanning a 90 nm band about a center wavelength of 566 nm. The light from this astro-comb is used to calibrate the HARPS-N astrophysical spectrograph for precision radial velocity measurements. The comb-calibrated spectrograph achieves a stability of $\sim$ 1 cm/s within half an hour of averaging time. We also use the astro-comb as a reference for measurements of solar spectra obtained with a compact telescope, and as a tool to study intrapixel sensitivity variations on the CCD of the spectrograph.