What is "astro-comb"

An astro-comb is a new type of frequency comb which promises to increase the resolution of existing spectrographs by nearly a hundredfold, allowing it to be used as an observational tool in astronomy and detect redshift wobbles caused by smaller exoplanets than is currently possible. Existing frequency combs were too precise to be useful for astronomy, with "teeth" too close together. In other words, the repetition rate or the frequency spacing between the comb lines was much smaller (<1 gigahertz) than that required for astronomical applications (~tens of gigahertz or more). The first astro-comb will be installed in 2009 or 2010 on the William Herschel Telescope on the Canary Islands. The device was developed by a team led by Chih-Hao Li of Harvard University.

The astro-comb uses a pulsed laser to filter starlight before feeding the signal into a spectrograph. It has the potential to revolutionise astrophysical spectroscopy.