About this tool: Thirteen telescopes operated by 11 nations, all on the 4,207-metre summit of Mauna Kea on Hawaiʻi Island. Filter by wavelength regime to see optical, infrared, submillimetre or radio instruments. The summit is closed to the general public; the Visitor Information Station at 2,800 m runs free public stargazing programs most clear evenings — see our Hawaii Stargazing Forecast for tonight’s conditions and our Mauna Kea stargazing guide for the full background.