Image from video Footage of the CSO telescope removal courtesy Caltech

(BIVN) – The Leighton Telescope has been removed from the Caltech Submillimeter Observatory on Maunakea, and now the decommissioning of the CSO has been paused until spring 2024.

Caltech reported on Thursday that the telescope will be shipped to Chile for re-use. After the winter, deconstruction of the dome and restoration of the site on the mountain summit will resume.

“The CSO decommissioning is a complex and multi-phase project,” said Caltech physics professor and CSO Director Sunil Golwala. “We made a lot of progress this summer and fall. In the spring, when weather permits, we will resume decommissioning with the removal of the building that housed the telescope and restoration of the site.”

According to Caltech, the following items were accomplished during the first phase of the decommissioning:

• The telescope, including its mount, was taken out of the observatory dome and was removed from Maunakea.
• The cesspool was confirmed to contain no remaining liquid contents.
• Interior demolition began. Two roll-off containers were filled with debris, mainly insulation, drywall, and plywood, and were removed from Maunakea.
• Electrical power to the observatory was cut off and the main circuit breaker was shut off. The electrical transformer feeding the site will be removed by HELCO.
• The site was inspected for rodents, as required by the county building permit.
• Underground utilities, including sewer, water, electrical, communication, and grounding grids, were mapped using ground-penetrating radar so that they can be easily located during the demolition process.
• An Independent Decommissioning Construction Monitor and a Cultural Monitor were present at all appropriate phases.

In the spring, when decommissioning is set to resume, the following is planned:

• Interior demolition will be completed and the observatory dome will be removed.
• The foundation will be removed along with the cesspool, its remaining solid contents, and all underground utilities.
• The ground underneath the foundation and the cesspool will be sampled for chemicals of potential concern.
• The site will be monitored for the appearance of invasive species.
• The land will be restored to the fullest extent consistent with the permits guiding the decommissioning.
• Cultural, construction, and archeological monitors will be present at all appropriate phases.

Golwala says that following the completion of restoration, the site will be monitored for three years, “primarily to document repopulation by flora and fauna.”

The total cost of decommissioning the CSO, which first came online in 1987, is expected to exceed $4 million. Caltech says the project “is being funded primarily by the Gordon and Betty Moore Foundation, while the removal of the telescope for reuse is being funded by the Heising-Simons Foundation.”