WAILUKU » The summit of Haleakala is the best site in the world for the proposed Advanced Technology Solar Telescope, according to the National Science Foundation.

The conclusion was reached after a two-year study of 70 sites around the world, including Mauna Kea and Mauna Loa, for the telescope's observatory, the foundation said in a supplemental draft environmental impact statement.

Haleakala is the only site that satisfies the goals of the world's largest optical solar telescope, it said.

The primary goals of the proposed telescope project are to understand solar magnetic activities and variability, the study said.

It said the sun serves as a key resource for understanding “;the underpinnings of astrophysics and our understanding of magnetic plasmas,”; and sun activity drives “;space weather.”;

“;Space weather creates hazards for communications to and from satellites, as well as for astronauts and air travelers,”; the report said.

It noted the sun also affects Earth's climate.

“;The key to understanding solar variability and its direct impact on the earth rests with understanding all aspects of solar magnetic fields, which in turn control the fluctuating sun,”; it said.

The proposed 92-foot-long telescope would be located in Haleakala National Park, housed in an observatory measuring 84 feet in diameter and 143 feet high. It would be situated east of the C.E. Kenneth Mees Solar Observatory, on land managed by the University of Hawaii Institute for Astronomy.

Resistance to the project has come from some native Hawaiians, who consider Haleakala a sacred place.

Park managers opposed construction of the telescope after the initial draft environmental impact statement was released in 2006, saying it failed to adequately evaluate numerous cumulative adverse impacts to the park's resources, visitors and overall operation.

The latest statement addresses the operation of commercial vehicles in the park during the construction and operation of the telescope. The $161 million project needs a special-use permit from the National Park Service to operate the vehicles.

The telescope is a project of the National Solar Observatory operated by the Association of Universities for Research in Astronomy under a cooperative agreement with the National Science Foundation, according to the project's Web site. The supplemental draft environmental impact statement was prepared on behalf of the foundation by KC Environmental Inc.

The deadline for public comments is June 22.