The mirror of the world's largest telescope, which scientists say will provide new views of how the universe evolves, was completed. The last of 36 half-ton hexagonal segments was lowered into place at the W. M. Keck Observatory at the 13,600-foot summit of the dormant Mauna Kea volcano on Hawaii Island. Together the segments form a 10-meter mirror surface. The $94-million telescope is four times the power of the Hale Telescope on Mt. Palomar in Southern California, which has been astronomy's preeminent telescope, said Jerry Nelson, astronomy professor at UC Berkeley and the telescope's principal designer.