COMMENTS ON THE NEXT-GENERATION OF GROUND-BASED SOLAR TELESCOPES

The development of telescope capabilities tends to go in spurts. These are triggered by the availability of new techniques in optics, mechan ics and/or instrumentation. So has nighttime telescope technology deve loped since the construction in the nineteen-forties of the 5-m Hale t elescope, first by the introduction in the sixties of high efficiency electronic detectors, followed recently by the production of large 8- to 10-m mirrors and now by the implementation of adaptive optics. In s olar astronomy, major steps were the introduction of the coronagraph b y Lyot in the nineteen-thirties and the vacuum telescope concept by Du nn in the sixties. In the last thirty years, telescope developments in solar astronomy have relied primarily on improved instrumental capabi lities. As in nighttime astronomy, these instruments and their detecto rs are reaching their limits set by the quantum nature of light and th e telescope diffraction. Larger telescopes are needed to increase sens itivity and angular resolution of the observations. In this paper, I w ill review recent efforts to increase substantially the telescope capa bilities themselves. I will emphasize the concept of a large all-wavel ength, coronagraphic telescope (CLEAR) which is presently being develo ped.