Coordinated observations of the collision of NASA's Deep Impact mission with comet 9P/Tempel 1 by the Subaru, Gemini and Keck telescopes on Mauna Kea delivered surprising new insights into the ancestry and life-cycles of comets. Specifically, materials beneath the comet's dusty skin shows striking similarities between two families of comets where no relationship had been suspected.

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More info: Subaru telescope web page