SEATAC - Tyee High School students will earn credit this fall for gazing at stars through what may be the state's only student-built observatory.

About three years ago, plans to build an observatory above the science building were dropped when the school's remodeling project was trimmed.

"We said forget it. We'll do it ourselves," said Warren Levenhagen, chemistry and physics teacher.

About 200 students have earned extra science credits by helping Levenhagen build the 27-foot-tall wood and steel structure on the edge of the school's parking lot.

As a sophomore, Greg Landon helped draw the plans on a computer. Now Landon, 18, is about to graduate, but intends to help complete the observatory before heading off to college to study engineering.

"I just didn't want to leave it," Landon said. "I definitely want to see it finished."

Junior Steve Mandelin, 17, said he has had fun digging holes and pounding nails. "You can do hands-on stuff rather than memorize formulas and all that other garbage," said Mandelin, who wants to be a pilot. "It's going to give our school something (others) don't have."

Few schools in the state have their own observatory, and Levenhagen said he hasn't heard of any being built by students.

The material was "scrounged" from left-over school-remodeling projects. Students held fund-raisers to pay for other items. "Sometimes we've just flat-out asked for money," said Levenhagen, who has put in about 3,500 hours on the project.

A concrete floor will be poured Tuesday, and a retractable roof will be added sometime this summer. When complete, it will be worth about $7,000 to $8,000.

"I don't think I've ever done anything this complex," said Levenhagen, who built his own home. "Everything is round. Nothing is square, and you have to cut everything at crazy angles."

Construction and design were difficult, but that was nothing compared to obtaining the building permit from King County and then the city of SeaTac after the area incorporated last year, he said. It took 587 days.

"The hardest thing for us was to communicate to them what we wanted," he said. "We're not professionals, and they've never dealt with an observatory before."

A reflecting telescope with a 10-inch-wide mirror will be installed before the first Tyee astronomy class begins in the fall. More than 56 students have signed up so far.