The state announced a "notice to proceed" for the Thirty Meter Telescope project at a news conference Thursday.
Hawaii Gov. David Ige said it was the final legal step in a long, often contentious, process, and that construction is expected to begin sometime this summer.
"We will proceed in a way that respects the people, place and culture that make Hawaii unique," Ige said. "We are all stewards of Mauna Kea. The state has an obligation to respect and honor the unique cultural and natural resources on this special mountain."
Scientists say the summit is one of the best places on Earth for astronomy. The telescope would be three times as wide as the largest existing visible-light telescope in the world, with nine times more area. Several telescopes and observatories are already on the summit.
But opponents say the telescope will desecrate sacred land atop Mauna Kea, the state's highest peak and a place of religious importance to Native Hawaiians.
State and county officials arrived at the summit early Thursday morning to remove Native Hawaiian structures that had been built on land where the telescope will be constructed.
Kealoha Pisciotta, a Native Hawaiian activist who has led some of the protest efforts, said officials were only allowing astronomers through and blocking the road to the summit for everyone else, including Hawaiians who asked to go pray. The Department of Land and Natural resources said one person was arrested by county police for obstruction.
Native Hawaiians have used the structures for years, Pisciotta said, and she considers the removal of the structures to be desecration and discriminatory.
"What's the argument for taking them down? It's completely discriminatory. It's hostile to the Native Hawaiian people," she said. "These are places of worship and the places where we lay our offering and our prayer."
She said their rights to religious freedom are being violated.
"If someone went into a church and took down the crucifix or you know the cross, how would that be treated?" Pisciotta asked.
Pisciotta said an overnight solstice ceremony was planned on the mountain and worried that they would be denied access. The group was also planning to honor an elder who recently died.
"They know that we go up during solstice and equinox," said Pisciotta. "We were preparing to head up tonight for the solstice and to honor him."
A spokesman for the state attorney general's office said in an email that officials will not restrict access for that event.
The new telescope will allow astronomers to reach back 13 billion years, to the time just after the big bang, and scientists say it will help answer fundamental questions about the advent of the universe.
"The world is not black and white. This is not an oil pipeline. It is a telescope to look into the very origins of life in the universe," Ige said. "We have worked a long time to hear each other and to make a choice as a collective community. To the many who support this project, let us always hold all views as one. Let us always touch the mountain as we gaze out beyond the sky."
Plans for the telescope date to 2009, when scientists first selected Mauna Kea. The project won a series of approvals from Hawaii, including a permit to build on conservation land in 2011.
Protests disrupted a groundbreaking and Hawaiian blessing ceremony at the site in 2014. Construction stopped in April 2015 after 31 protesters were arrested for blocking the work. A second attempt to restart construction a few months later ended with more arrests and crews retreating when they encountered large boulders in the road.
Hawaii Attorney General Clare Connors said the state Supreme Court ruling must be respected, but that people's right to free speech is also protected and that the conversation should continue.
"It is important that it not stop even as the telescope is constructed," Connors said. "For safety we encourage that this conversation happens somewhere other than on Mauna Kea."
The attorney general said she hopes there will be no more confrontations.
"We are all in this together and we hope that everyone who comes to Mauna Kea takes responsibility for their actions, their words and their decisions," she said. "The safety of our community depends upon people respecting the law and each other."
A group of universities in California and Canada make up the telescope company, with partners from China, India and Japan.
Thirty Meter Telescope spokesman Scott Ishikawa said that they hope to begin construction as soon as possible but that they needed to work with county and state officials on exact timing.
"We remain committed to being good stewards of Mauna Kea, and to honoring and respecting the culture and traditions of Hawaii," said Henry Yang, chair of TMT International Observatory Board of Governors. "It has been a long process to get to this point."
Richard Ha, a Native Hawaiian farmer who lives on the Big Island and supports the project, said he thinks the telescope will provide an opportunity for the community to learn and grow.
He does not practice religion on the summit, he said, but he does visit Mauna Kea and respects the connection Native Hawaiians have to the place.
"Once you get above the clouds, you're in a different world," Ha said. "You're in the universe and it's just amazing to look up and see so many stars. It makes you feel like humans are just a small part."