For the first time, a telescope on the Hawaiian volcano Maunakea has been fully decommissioned — it was dismantled, removed, and its site was restored to previous conditions. The effort comes under an agreement between the University of Hawaii and the Maunakea Stewardship and Oversight Authority, designed to smooth tensions over the construction of a new telescope on the mountain: The Thirty Meter Telescope.
Since the 1960s, 13 telescopes have been built on Maunakea, a place that's sacred to the indigenous people of the Hawaiian islands because it is where the earth meets the sky. As such, each new Maunakea observatory has been met with dismay by protestors who believe the building of new telescopes on this volcanic mountain is sacrilegious. The astronomical community, however, has struggled to find a balance between their scientific research plans and the needs of indigenous Hawaiian culture. That's because Maunakea offers uniquely pristine skywatching conditions. Things reached a head with protests against the planned Thirty Meter Telescope (TMT), which, if constructed, would be the second largest telescope in the world — and the largest on Maunakea.
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However, question marks still hang over the future of the TMT. The National Science Foundation (NSF) has said it can only provide funding for one of either the TMT or the Giant Magellan Telescope, which is planned for construction in Chile. A panel was convened to determine which project the NSF should help fund. The losing observatory may still be able to go ahead should it acquire enough private funding, but the fate of the Thirty Meter Telescope on Maunakea remains far from certain.
Still, experts are getting prepared for the event that the TMT does indeed go forward.
Until recently, the telescopes on Maunakea were managed by the University of Hawaii, but in an attempt to work more closely with indigenous Hawaiians, management of the observatories has been handed over to the newly established Maunakea Authority. The Authority contains representatives from local government, the university, as well as the observatories themselves. It is also intended to feature people with experience and understanding of Hawaiian culture in order to help guide the most appropriate use of the mountain.
As part of the handover — and as part of a deal to hopefully obtain a permit for construction of the Thirty Meter Telescope — the University of Hawaii has agreed to decommission three observatories on the mountain. Now, the first of these — the University of Hawaii Hilo's 36-inch Hōkū Keʻa Telescope, which was used for teaching — has been removed.
The telescope couldn't just be messily torn down; rather, its closure had to follow a four-point "Decommissioning Plan" as part of the University of Hawaii's Maunakea Comprehensive Management Plan. The four points begin with the notification of intent to close a telescope; this is followed by performing environmental due diligence and site assessments. Next, careful deconstruction and removal of the telescope, its observatory dome, associated buildings and infrastructure can take place. Finally, the site must be restored to its original state, which also involves monitoring the area for three years to see what impact the restoration had on encouraging local wildlife.
"Maunakea warrants the highest levels of stewardship, and we remain steadfast in our collaborative efforts to honor and protect the cultural and environment significance of this āina [the Hawaiian word for 'land']," the Chancellor of the University of Hawaii Hilo, Bonnie Irwin, said in a statement. "The removal of Hōkū Keʻa reflects the university's ongoing pledge to reduce the presence of telescopes on Maunakea."
The decommissioning of Hōkū Keʻa began in April and cost $1 million. More expensive is the removal of the Caltech Submillimeter Observatory (CSO), which is much larger with a radio dish that's 10.4 meters (34 feet) in diameter. Having seen first light in 1986, the CSO actually closed in 2015 having been superseded by new instruments such as the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile.
The dish belonging to this submillimeter telescope, which was named the Leighton Telescope after astronomer Robert Leighton who first proposed the CSO back in 1973, was dismantled just before Christmas 2023. Removal of the dome and the rest of the observatory’s infrastructure is already underway, to the tune of $4 million.
The third telescope to be removed will be UKIRT, the United Kingdom Infrared Telescope, a 3.8-meter (150-inch) telescope originally owned and managed by the U.K., but which, in 2014, was handed over to the University of Hawaii. Since then, it has continued operating in an automatic, unassisted mode. As per the agreement with the Maunakea Authority, two further telescopes must also be removed from the mountain by 2033 if the TMT manages to find a way to go ahead.
