It was the perfect Eagle Scout project, something befitting that name, a task that soared into the sky and beyond into space. The astronomy dome at Monrovia High School, opened in 1983, had gradually fallen prey to neglect and changing curriculums until, finally, it wasn't used at all. Thursday, before more than 100 school district and city officials, teachers, students and parents, the refurbished dome and its repaired telescope was reopened with a Second Light celebration. Pamela Gonzales, the school's astronomy teacher, said a First Light celebration marks the first use of a telescope. Second Light events mark the first use of reconditioned telescopes.