The second asteroid-tracking telescope at Haleakala is expected to be operational next month.

The device, part of the Panoramic Survey Telescope and Rapid Response System, is one of four powerful telescopes the University of Hawaii plans to set up to detect large asteroids and comets heading toward Earth.

The first Pan-STARRS telescope was installed at Haleakala in 2010. A comet spotted by the telescope came close enough to Earth to be visible with binoculars earlier this year.

The Maui News reported that general contractor Armstrong Pacific retrofitted the old University of Tokyo Magnum observatory to accommodate Pan-STARRS 2.

The company raised the foundation, replaced structural steel and upgraded mechanical and electrical systems to support the new telescope.

Working conditions at the site 10,000 feet above sea level presented challenges for the 30 workers on the project.

The altitude affected workers, as did the cold, the rain and the sleet, said Kevin Keller, Armstrong Pacific project manager. They had to work closely and communicate with cultural advisers. And there was a 1-hour, 45-minute one-way commute, he said.

Still, workers were able to complete the $2 million project on time and under budget, he said.

Keller said in an interview last week that unlike most jobs there were "zero tolerances." The anchor bolts and mechanical and electrical work "had to be perfect." When the crane picked up the telescope, "it fit perfectly in place," he said.

The addition of the second Pan-STARRS telescope will create "by far the most powerful wide-field imaging system in existence," Nick Kaiser, principal investigator of Pan-STARRS at the UH Institute for Astronomy, said earlier this year.

The Pan-STARRS design combines relatively small mirrors with large digital cameras to create a viewing system that can observe the entire sky several times each month.