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The Daniel K. Inouye Solar Telescope (DKIST)

The DKIST Telescope Enclosure and Support and Operations building at the site on Haleakala, HI

In the early 2000s, the National Science Foundation (NSF) proposed building the world’s largest world’s largest optical solar telescope atop the summit of Maui’s Haleakalā Volcano.  With a resolution of 25 kilometers, when it is completed in 2019 the $344 million the Daniel K Inouye Solar Telescope (DKIST) will have the equivalent zoom power to scrutinize the contours of an inch-wide coin from 100 km (62 mi) away.

That will allow scientists to examine out the long sought-after phenomenon of magnetic flux tubes – twisted and tangled filaments that can channel energy into the corona. It is hoped that observation of these magnetic flux tubes will help to answer the so-called “coronal heating problem”: why the corona is millions of degrees hotter than the photosphere, the visible surface of the sun.

When the DKIST was initially proposed, however, many Native Hawaiians expressed serious concerns about the planned construction atop Haleakalā volcano. Native Hawaiian culture celebrates a profound spiritual connection with the land, and few places are considered more sacred than high mountain peaks. In ancient times they were regarded as wao akua – the “realm of the gods” – where deities and demigods walked the earth. Today, these mountains are still treated with reverence, places many Hawaiians visit to honor ancestors and practice spiritual traditions.

Such cultural concerns prompted a halt to construction on another privately-funded telescope, the “Thirty Meter Telescope” (TMT), on the dormant volcano of Mauna Kea in 2015. At 18 stories, the TMT would have been the largest humanmade structure on Hawaii Island on the highest mountain in the Pacific.

Because the DKIST was a federally funded project, the National Science Foundation (NSF) was required to satisfy U.S. historic preservation rules and carry out an environmental review under the National Environmental Policy Act (NEPA). At its most basic level, NEPA requires government agencies to engage in a review process intended to discover any significant environmental, economic, social, or public health impacts before a decision is made.

DSKIT Observatory Gallery // Ruth Kneale

A key element of this review process is the solicitation of public comments. Acutely aware of Native Hawaiian cultural objections, the NSF used the NEPA process to engage in extensive discussion with local communities and other agencies on possible alternatives and methods of mitigation. 

After hours of public testimony and countless meetings with Native Hawaiian leaders, NSF adopted numerous design changes to better respect native beliefs. While the proposed TMT telescope would have had a footprint of almost 5 acres, including its roads and parking lot, the plat for DKIST will be nearly 10 times smaller. Workers and scientists were also required to undergo cultural training and watch an educational video about the role of the mountain in Hawaiian culture and spirituality.

Finally, a dressing area was built at the summit for Hawaiian practitioners conducting ceremonies at the ahu, and DKIST established a $20 million program at Maui College that combines Hawaiian culture with science education.

Although many Native Hawaiians remained opposed construction of the nearly 14-story high telescope and that opposition should be respected, the NEPA process provided a platform for real dialogue between project proponents and Native Hawaiians. This resulted in the adoption of a series of mitigation measures that made the DKIST telescope as minimally intrusive as possible.

A comparison of the vastly different outcomes between the TMT telescope, did not require NEPA review, and the DKIST telescope, which underwent comprehensive environmental and historic review, also lends further credence to the fact that NEPA more often than not improves projects.


[1] “Final Environmental Impact Statement: Advanced Technology Solar Telescope.” National Science Foundation. 7/24/2009. Available at:

[2] “Record of Decision: Advanced Technology Solar Telescope.” National Science Foundation, 9/29/2009. Available at:

[3] “Record of Decision for the issuance of a Special Use Permit for the use of commercial vehicles within Haleakala National park to access the Haleakala Observatories.” United States Department of the Interior. 04/30/12. Available at:

[4] “NSF’s Environmental Compliance.” National Science Foundation. Available at:

[5] Richard Moss. “World’s biggest solar telescope set for 2019 completion in Hawaii.” News Atlas, 2/14/2017. Available at:

[6] Ilima Loomis. “How the world’s largest solar telescope rose on Maui while nearby protests derailed a larger scope.” Science Magazine, 4/1/2017. Available at:



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