PUKALANI, Maui — The federal government's Advanced Technology Solar Telescope, a controversial project to study the sun that's $23 million in planning and 10 years in the making — so far — will receive the money it needs to be built atop Haleakalä.

After the completion of a long-awaited environmental impact statement during the summer, National Science Foundation Director Arden Bement officially selected Haleakalä last week as the site of the planned 143-foot-tall telescope and funded the $300 million project, according to a decision made public in Tuesday's Federal Register.

The project would be the world's largest optical solar telescope, with a 13-foot-diameter main mirror that would help provide the sharpest views ever of the sun.

Contractors will build the telescope over the next seven years on a half-acre within the University of Hawai'i's Science City, a cluster of observatories near the summit, UH Institute for Astronomy Assistant Director Mike Maberry said Wednesday.

However, Maberry said the state Board of Land and Natural Resources still needs to vote on the project before it can move forward. Nevertheless, he said he expects construction most likely to begin next fall.

"This will allow for the greatest advancement in our understanding of the star that allows life to exist on our planet," Maberry said.

However, the project's opponents, including kahu Charles Kauluwehi Maxwell Sr., said the telescope is unnecessary, ugly and extremely disrespectful to the Hawaiian culture. Haleakalä is considered a sacred place, in part, because monarchs were buried nearby.

"Now the battle starts," said Maxwell, 72. "It's not over. Native Hawaiians should gather with me, and we will all lay our bodies down in front of the tractors. This will be my last stand.

"There's enough junk up there already to completely annihilate the spirituality of Haleakalä," he said.

UH manages the 18-acre Science City, which is home to about a dozen observatories and numerous large and small telescopes, some of which are owned by the U.S. Air Force and remain top secret.

Native Hawaiian groups have been invited to a discussion of the decision from 3 to 5 p.m. Tuesday at the UH Institute for Astronomy's Maikalani Advanced Technology Research Center at 34 Ohia Ku St. in Pukalani. It will be hosted by Caroline Blanco, assistant general counsel to the National Science Foundation.