With a concept first proposed in 1977, telescope designers at the University of California (Terry Mast) and Lawrence Berkeley Labs (Jerry Nelson) had been developing the technology necessary to build a large, ground-based telescope. With a design in hand, a search for the funding began. The Keck I telescope began science observations in May 1993, while first light for Keck II occurred on October 23, 1996.
The Keck Observatory is managed by the California Association for Research in Astronomy, a non-profit 501(c)(3) organization whose board of directors includes representatives from Caltech and the University of California.
Each Keck Observatory telescope sits on an altazimuth mount. Most current 8–10 m class telescopes use altazimuth designs due to the reduced structural requirements compared to older equatorial designs. This mounting style provides the greatest strength and stiffness for the least amount of steel, which, for Keck Observatory, totals about 270 tons per telescope. The total weight of each telescope is more than 300 tons. Two of the proposed designs for the next generation 30 and 40 m telescopes use the same basic technology pioneered at Keck Observatory, a hexagonal mirror array coupled with an altazimuth mounting.
According to wikipedia