Leighton telescope at the Caltech Submillimeter Observatory on August 11, 2023, after removal of primary mirror panels. (courtesy Caltech Submillimeter Observatory)

(BIVN) – The removal of the Caltech Submillimeter Observatory from Maunakea is underway, a major part of the decommissioning of the telescope from the summit area.

“Our team has started working inside the observatory to take apart the telescope and get it ready for removal,” said Caltech physics professor and Caltech Submillimeter Telescope (CSO) Director Sunil Golwala in a news release. “Since June, the aluminum panels that make up the reflecting surface of the telescope have been removed and packed. The secondary mirror and its support structure were removed last week.”

“We have also started to mobilize some of the large equipment needed to remove the telescope parts from the observatory up the mountain,” said Golwala.

The CSO first came online in 1987.

From the Caltech news release:

In June, Caltech shared its plan to disassemble the telescope and its mirror into parts, reversing the process used to assemble the telescope in the 1980s and mitigating the need for road closures and other disruptions to the area. As the telescope is disassembled, parts will be staged in the CSO parking lot prior to transport down the mountain. Equipment needed for telescope disassembly includes a telehandler (forklift), a manlift, and an anchor baseplate, all of which have been delivered to the CSO.

During September, it is expected that a 120-ton crane will be transported to the CSO to remove the larger parts of the telescope from the observatory dome. A smaller crane will be mobilized later for disassembly of the primary mirror backup structure and for packing telescope parts into containers for transport down the mountain.

Also in September, Goodfellow Bros., the general contractor that will remove the CSO buildings and will carry out restoration of the site, will start work. “Goodfellow Bros. will pump out the cesspool and will undertake interior demolition of the enclosure this fall. Removal of above-ground structures and below-ground infrastructure will be deferred to next spring because of inclement winter weather. Restoration to the level approved under our permit will occur next summer after all structures are removed,” said Golwala.

“To aid the community in monitoring the progress of decommissioning, we will be tracking the process on our website with pictures and short updates,” said Golwala.

Leighton telescope at the Caltech Submillimeter Observatory on August 24, 2023, before removal of primary mirror panels, feedlegs and secondary mirror assembly. (courtesy Caltech Submillimeter Observatory)

“In accordance with the permits guiding the decommissioning, cultural, construction and archeological monitors will be present at all appropriate phases,” said Golwala. The cultural monitor conducted an orientation last week for all personnel working on site and will provide this orientation to any incoming personnel. A blessing was performed at the site to mark the decommissioning, with representatives of Caltech and Center for Maunakea Stewardship in attendance.

The cost of deconstruction and site restoration is expected to exceed $4 million. The decommissioning of the telescope is being carried out according to the Conservation District Use Permit (CDUP) issued by the state’s Department of Land and Natural Resources (DLNR) in January 2022. CSO is the first observatory to be removed under the 2010 Decommissioning Plan for Maunakea Observatories. All the astronomical instruments were removed from the facility in 2015 except the telescope itself.