Following great success in the creation of the Keck Observatory, scientists at the California Institute of
Technology and the University of California have begun to explore the scientific and technical prospects
for a much larger telescope. The Keck telescopes will remain the largest telescopes in the world for a
number of years, with many decades of forefront research ahead after that. Though these telescopes
have produced dramatic discoveries, it is already clear that even larger telescopes must be built if we
are to address some of the most profound questions about our universe. The time required to build a
larger telescope is approximately ten years, and the California community is presently well-positioned
to begin its design and construction. The same scientists who conceived, led the design, and guided
the construction of the Keck Observatory have been intensely engaged in a study of the prospects for
an extremely large telescope. Building on our experience with the Keck Observatory, we have concluded
that the large telescope is feasible and is within the bounds set by present-day technology. Our reference
telescope has a diameter of 30 meters, the largest size we believe can be built with acceptable risk. The
project is currently designated the California Extremely Large Telescope (CELT)
