Caltech Submillimeter Observatory

The Caltech Submillimeter Observatory spent nearly three decades studying the sky in submillimeter wavelengths from the summit of Mauna Kea, Hawaii, before its telescope was dismantled in the 2020s.

About Caltech Submillimeter Observatory

The Caltech Submillimeter Observatory (CSO) was a 10.4-metre (34 ft) submillimeter-wavelength telescope on Mauna Kea, Hawaii, sited alongside the James Clerk Maxwell Telescope within the Mauna Kea Observatories complex.

History

CSO began observing the terahertz radiation band in 1986 and closed on 18 September 2015. Disassembly of its telescope started in August 2023 as the first observatory removed under the University of Hawai'i's Maunakea Comprehensive Management Plan decommissioning process, a project expected to cost more than $4 million and finish by summer 2024.

Location & getting there

The site sits at roughly 4,136 metres (13,570 ft) on Mauna Kea, Hawaii, one of the highest and most astronomically important mountains in the world.

Visiting Caltech Submillimeter Observatory

CSO is decommissioned and its telescope has been removed, so there is no public access or tour to offer here. Mauna Kea's visitor information station and other active observatories nearby still welcome visitors; check current access rules for the summit before travelling, as they can be restrictive at altitude.

See your named star from here

CSO observed the sky in wavelengths invisible to the human eye and is no longer operating, so it was never a place to look at a named star directly. Mauna Kea remains one of the best sites on Earth for stargazing, though, so browse other observatories nearby, check your star's coordinates in the catalogue, or name a star to get started.