Caltech Submillimeter Observatory

The Caltech Submillimeter Observatory was a 10.4-meter diameter submillimeter wavelength telescope situated alongside the 15-meter James Clerk Maxwell Telescope at Mauna Kea Observatories. It was engaged in submillimeter astronomy, of the terahertz radiation band. The telescope closed on September 18, 2015. As of April 2019, the telescope is set to be dismantled and its site remediated in the near future as part of the Mauna Kea Comprehensive Management Plan.

Source: Wikipedia