The Hoku Kea Observatory, the University of Hawaii’s educational telescope on Mauna Kea, is no more.

The telescope was the first of five Mauna Kea observatories slated for removal as part of the university’s Maunakea Comprehensive Management Plan and, as of the end of May, was the first to be completely removed from the summit.

“We have mixed feelings about it,” said UH Hilo Chancellor Bonnie Irwin. “We’re happy that it’s the first observatory to be decommissioned. It shows UH’s dedication to taking care of the mauna.

“But now UH has a telescope without a home,” Irwin continued.

Hoku Kea was built in 1968 by the U.S. Air Force and was transferred to UH in 1970 and to UH Hilo in 2003. But it has not actually functioned as an observatory for more than a decade.

A new telescope installed in 2010 was found to be faulty and was never operational. Because repairing the telescope would be too expensive, the faulty instrument was removed in 2018.

UH purchased a replacement telescope, but because it did so at about the same time that Hoku Kea was slated for decommissioning, it was never mounted at the observatory and has been used to view the sky on only a single occasion.

A new teaching observatory was considered to be sited at Halepohaku, the midlevel facility on Mauna Kea, but that plan has been put on hold, said Greg Chun, executive director of UH’s Center for Maunakea Stewardship.

With a new state agency, the Maunakea Stewardship and Oversight Authority, taking over management of the Mauna Kea summit, Chun said any decisions about the replacement observatory will wait until the new managers have a concrete management plan for the area.

However, Chun said it was important for UH to fulfill its own commitment to decommissioning five Mauna Kea observatories.

While all of Hoku Kea’s building materials and infrastructure have been removed, Chun said the site is conducive for visitors to watch the sunrise and sunset, so the site has been graded to be used as a viewing location.

Deconstruction began in late April and took roughly 2-1/2 weeks and about $1 million to complete. Six dump trucks and nine trailer loads were needed to remove debris from the structures, while the site was restored and graded using infill material from elsewhere on the mountain.

“You can’t really tell that anything was there at all,” said Karl Halemano, construction and cultural monitor for the Center for Maunakea Stewardship.

Chun said UH and the Center for Maunakea Stewardship took precautions |to ensure that the deconstruction process was respectful of the natural environment, while Halemano said he led cultural protocols with the construction crews each morning during the decommissioning process.

“It’s a small project, but it’s very important to me as a Native Hawaiian,” Halemano said. “It’s such a privilege to be up there, to be a part of this cleaning.”

Meanwhile, decommissioning of the Caltech Submillimeter Observatory, the second summit telescope to be removed, continues. Caltech announced Friday the observatory dome and other buildings have been entirely removed; Chun said removing the building’s foundations is still to be done.

That process — which Chun said is more intensive than the Hoku Kea removal, involving as it does a much larger building — is estimated to be completed by the end of the year and cost more than $4 million. Once finished, Caltech will monitor the site for another three years to document its repopulation by flora and fauna.

While the Comprehensive Management Plan still plans for three more summit observatories to be removed, Chun said those projects will be on hold for the time being, until the Maunakea Stewardship and Oversight Authority determines its plan for the summit area. UH made a commitment to the university’s Board of Regents in 2023 to remove two telescopes before the MKSOA assumes full management of the summit lands by July 2028.