Maui County police were on the scene in Puunene on Thursday night during a demonstration aimed at blocking a shipment of parts and material headed to an observatory under construction at the summit of Haleakala.

County spokesman Rod Antone said officers were expected to honor the protesters’ right to freedom of speech but also make sure laws were enforced and safety maintained.

“It’s like walking a tightrope,” he said.

Members of Kako‘o Haleakala were hoping for a replay of their first protest vigil June 25, when an estimated 200 people prevented a group of oversize vehicles from leaving the Central Maui Baseyard near Puunene for a planned journey to the construction site of the $340 million Daniel K. Inouye Solar Telescope.

The group, which says it views the 14-story telescope as a desecration of a sacred mountain and is inspired by the Mauna Kea “protectors” who have so far thwarted construction of the Thirty Meter Telescope, started showing up about 7 p.m. in anticipation of a peaceful “aloha aina gathering to protect Haleakala” featuring prayer, chanting and song.

The shipment was scheduled to start for the summit between 10 p.m. and 2 a.m.

Organizers of the protest vowed to do whatever it takes to prevent a convoy of trucks from reaching the mountain.

Telescope project manager Joseph McMullin said that while project officials respect the right of others to demonstrate, “we expect our legal rights to also be respected, including access to roads.”

The Maui Police Department issued a statement Thursday saying the department “respects the rights for people to demonstrate peacefully. We will respond in an appropriate manner.”

Antone said county officials were concerned demonstrators would spill out onto Mokulele Highway, a key link between Kahului and Kihei.

The stretch of highway is notorious for speeding traffic and can be dangerous, as illustrated by last month’s triple-fatality collision in which three men were thrown from a pickup truck.

“If (the demonstrators) block the highway, we’re afraid we’re going to have a bad ending,” Antone said.

Formerly known as the Advanced Technology Solar Telescope, the Inouye Telescope is about 80 percent built at the University of Hawaii’s Science City area at the summit of the 10,000-foot Maui mountain.

When the project is completed in 2019, it is expected to be the world’s most powerful solar telescope, enabling astronomers to study the sun in unprecedented detail.

A legal challenge to the project’s state-issued conservation use permit is being weighed by the Hawaii Supreme Court. Kila­kila o Haleakala, a group of Native Hawaiians that has been fighting the project for years, is hoping the high court will halt construction.

Kako‘o Haleakala leaders say they are upset that construction has been allowed to proceed while the project is being contested in court. That is the same argument expressed by opponents of the TMT project, which is also being contested in the state’s highest court.

McMullin said the materials being transported this week eventually will be needed at the summit to continue construction.

“If there are interruptions in our schedule, it does have a financial impact,” he said, adding that taxpayers could end up footing the bill.

The telescope is a project of the National Science Foundation, the Association of Universities for Research in Astronomy and the University of Hawaii.

The Kako‘o Haleakala demonstrators were expected to employ the same nonviolent “kapu aloha” protest approach that is the hallmark of the Mauna Kea protesters.

If the convoy is similar to the one attempted in June, it will include support vehicles and semitrailers that will haul the massive exterior siding of the observatory in an 18-foot-wide load at 2 to 5 mph.

Haleakala National Park last week announced that Crater Road and the park’s summit road will be closed to visitor traffic while the convoy moves to the summit. The roads will be closed to visitors through 2 p.m. Friday.

The project obtained a special use permit from Haleakala National Park to allow the convoy on its narrow roads.