Astro-comb

 ( Astronomical Spectroscopy ) 

An astro-comb is a type of frequency comb used in observational astronomy to increase the accuracy of wavelength calibration in . The increased accuracy reduces systematic errors and enhances detection of small variations in stellar radial velocities caused by smaller orbiting (e.g. Earth-mass planets), among other applications. Astro-combs are distinguished from conventional frequency combs by their focus on high repetition frequencies (with mode spacings of ≥10 GHz).

A green astro-comb was installed in January 2013 in the high accuracy radial velocity planet searcher in the northern hemisphere (HARPS-N) spectrograph at the Telescopio Nazionale Galileo on the Canary Islands. The device was developed by a team led by Chih-Hao Li of Harvard University. This astro-comb uses a pulsed laser to filter starlight before feeding the signal into a spectrograph. As of December 2016, it is gathering data from Venus to demonstrate its ability to discover exoplanets.

• Comb filter

• New Approaches to Precision Astrophysical Spectroscopy The Walsworth Group, October 10, 2016. Accessed November 30, 2016.
• TNG, HARPS-N and Astro Comb ready to characterize the first earth twin Fundación Galileo Galilei - INAF Telescopio Nazionale Galileo, July 28, 2015. Accessed December 1, 2016
• A green astro-comb to search for Earth-like planets Chih-Hao Li, SPIE, January 29, 2015. Accessed November 30, 2016.
• 'Astro-comb' helps search for Goldilocks planet Physorg.com, April 2, 2008. Accessed April 2, 2008.
• Astro-combing for Planets Astro Biology Magazine, April 9, 2008. Accessed April 11, 2008.
• Pulses to Find Planets, (Archive of Pulses to Find Planets Astro Biology Magazine, May 11, 2008. Accessed May 15, 2008. Based on a National Institute of Standards and Technology news release.)