Caltech Submillimeter Observatory

The Caltech Submillimeter Observatory ( CSO abbreviated ) is a radio telescope for wavelengths in the submillimeter range. Said primary mirror has a diameter of 10.4 m. The telescope is located near the 15 m James Clerk Maxwell submillimeter telescope ( JCMT ) and belongs to the Mauna Kea Observatory.

CSO and JCMT were tentatively connected in the 1990s for the first submillimeter interferometer. The success of this experiment laid the foundation for the development of further such interferometers, especially the Submillimeter Array and the Atacama Large Millimeter Array.