San Diego State University officials said they plan to build a powerful $2-million research telescope at the university’s Mt. Laguna Observatory in the Cleveland National Forest, 40 miles east of San Diego. They said they hope the 100-inch telescope, 6,100 feet above sea level, will attract astronomers from around the world. Ronald Angione, director of the observatory, said there are only about 15 telescopes in the world that large or larger. Caltech’s 200-inch telescope at Palomar Observatory is the second largest in the world.