Evolution of Ground and Space based Optical Systems during the Past 30 Years

The challenge today seems to be shifting from the question of technological feasibility to one of affordability. The demands of terrestrial and space astronomers continue to grow as new exciting results are obtained from their explorations. For two decades no major advances in telescope size have occurred, the main activity being to exploit the 4-meter class telescopes and see how the Soviet 6-meter system performs. In the space arena A pent-up demand for a dozen astronomical telescopes larger than any now in operation has evolved during the past decade, but funding realities have been such that only one is actually under construction, the 10-m keck segmented mirror telescope. The European Southern Observatory countries have now announced a governmental commitment to build a 16-meter system consisting of four 8-meter telescopes. The world optical industry has developed capabilities that will permit 8-meter class optical telescopes that in turn promise significant advances in scientific capabilities, but few observatories appear to be able to afford them. There thus is a maximum effort to achieve major cost reductions to bring this new class into affordability.