Forget the lei and mai tai greeting. When more than 2,500 astronomers from around the world converge on Honolulu for their triennial convention Aug. 3-14, they are likely to be welcomed by demonstrators.

Some of those who oppose the Thirty Meter Telescope view the 29th International Astronomical Union General Assembly at the Hawai‘i Convention Center — to be held in Hawaii for the first time — as an opportunity to get the truth out as they see it about the TMT controversy.

At the same time, they are angry and disappointed that the IAU has made no accommodation for opponents to formally address the assembly of astronomers about the $1.4 billion telescope planned for the summit of Mauna Kea.

“To come to Hawaii now and not address this situation would be completely disrespectful,” said Lanakila Mangauil, one of the leaders of the Mauna Kea “protectors.”

TMT foes say they are trying to arrange a simultaneous meeting at another venue in hopes of engaging at least some of the astronomers in a dialogue about the controversy.

Mangauil, a Hawaiian cultural practitioner from Hawaii island, said the truth is many of the world’s astronomers may be unaware of how important Mauna Kea is to the Hawaiian people and how the massive 18-story observatory will desecrate a sacred mountain.

“Our stance is we are not against astronomy,” he said. “Our issue is where they put the buildings.”

Founded in 1919, the IAU is the world’s largest professional body for astronomers. The group comes together every three years to share their research, talk about scientific issues and establish standards in the field.

The IAU also serves as the internationally recognized authority for assigning designations to celestial bodies and surface features on them. This is the same group that made worldwide news in 2006 when it demoted Pluto to dwarf planet status.

Three years later, at the 2009 meeting in Rio de Janeiro, the University of Hawaii teamed up with the American Astronomical Society to pitch Honolulu as host of the 2015 general assembly. Honolulu won out over Paris and Calgary, Canada. (Beijing was the 2012 host.) This year will be the first time the U.S. has hosted the event since Baltimore in 1988.

Conference officials estimate Hawaii will see an economic impact between $10 million and $20 million, with many of the astronomers from 75 countries also vacationing in the islands before and afterward.

Gov. David Ige embraced the IAU meeting warmly in a welcome letter appearing on the convention’s website, praising the group for choosing Hawaii, “where interest in astronomy is deeply entrenched in our island heritage.

“The heavens played a central role in ancient Hawaiian culture, and early Polynesians relied on their knowledge of the stars to successfully navigate thousands of miles across the open ocean. Today, Hawaii continues to be at the forefront of astronomical studies through the observa­- tories at Maunakea on the island of Hawaii and Haleakala on Maui,” Ige wrote, using the single-word spelling for Mauna Kea preferred in some quarters.

Some conference events are open to the public, including a couple of presentations of local interest. Polynesian Voyaging Society master navigator Kalepa Baybayan, who is also ‘Imiloa Astronomy Center navigator-in-residence, will discuss the use of stars by ancient Hawaiian navigators Aug. 4, while Gunther Hasinger, director of UH’s Institute for Astronomy, will talk about the development of modern astronomy in Hawaii Aug. 11.

Otherwise, the convention will be largely focused on the business of astronomy and the exploration of a vast universe, with scores of meetings to review the latest research on such phenomena as red supergiants, planetary nebulae, stellar explosions and star clusters.

Piero Benvenuti, deputy general secretary of the IAU, said the TMT and its troubles will not be discussed formally at the conference.

“We are aware of the current situation regarding the construction of the Thirty Meter Telescope and understand that it is a deeply complex and sensitive issue,” Benvenuti said in an email.

But organizers have no plans to alter a conference program that has been in the planning stages since 2009, he said.

“Given the timeliness of this situation, we do anticipate informal conversations about the topic to naturally occur. It is our sincere hope that moving forward, there will be an open, productive dialogue among all parties involved, creating a shared, long-term vision for Maunakea,” Benvenuti said.

The convention originally offered optional excursions to Mauna Kea. Planned were three different three-day excursions to Hawaii island, offered before, after and during the conference, with tours of Hawai‘i Volcanoes National Park and “the world’s foremost astronomical observatories” on Mauna Kea.

Those have since been canceled, however.

Meanwhile, construction remains on hold for the TMT, billed as what will be the most advanced and powerful optical telescope on Earth.

Mangauil said he would not be surprised if the project remains on hold through the duration of the convention to avoid any negative publicity while the world’s astronomers convene in Hawaii.

Asked if bad publicity might play a role in when the TMT would restart construction, University of California, Santa Cruz, astronomy professor Michael Bolte, a member of the TMT International Observatory Board, responded that: “There are a number of factors that will determine when construction will resume and we continue to work with the parties involved on when that will occur.”

In Honolulu, Benvenuti said organizers are aware there may be peaceful demonstrations near the convention center and have prepared a plan to protect convention attendees and demonstrators, if necessary. He said activities will be monitored closely to ensure the safety of participants.

UH law professor Williamson Chang said he’s disappointed the IAU decided to ignore an issue burning hot in the islands right now.

“They came because of Mauna Kea,” said Chang, who is of Native Hawaiian ancestry. “It is demeaning to think that astronomers are so single-minded and closed to the world that they would not care about the struggle on Mauna Kea.”

Chang said he and Hanalei Fergerstrom, a Native Hawaiian cultural practitioner from Hawaii island, with help from others, are hoping to organize an event that will bring together the “protectors” of Mauna Kea and astronomers attending the IAU convention.

The event, he said, is tentatively planned for the second week of the conference and will feature a panel of six to eight people representing both sides of the TMT controversy.

“They are the world’s greatest astronomers, and you would think some would be curious,” Chang said.

Mauna Kea Hui leader Kealoha Pisciotta said academics have the reputation of sitting in their ivory tower and staying above the fray.

“But this is a dialogue that needs to happen,” said Pisciotta, who has been fighting development atop Mauna Kea for decades. “You’d think scientists would want to hear both sides. I seriously hope they don’t try to be the ostrich with the head in the sand. The world is watching.”