Design concepts for future large aperture wide field of view UVIS optical systems

The Hubble Space Telescope (HST) has provided superb imaging and spectroscopic capability for studying galaxies, stars, and nebulae in the ultraviolet and visible (UVIS) wavelength regions, as well as in the near infrared. The HST is a 2.4-meter telescope with imaging, spectroscopic, and limited coronagraphic instrumentation. NASA plans to discontinue its operations in 2010. Next, generation ultraviolet and visible telescope capability to replace HST is currently under discussion. The new facility would include a very large aperture collector, ultra wide field of view (WFOV) imagery, precise wavefront control, and high UVIS efficiency. Such a facility would combine ultra wide FOV imagery that is diffraction-limited at Lyman-alpha (lambda=122 nm) with efficient broad spectral coverage. The design must also provide spectroscopic, and possibly coronagraphic, capability in addition to imagery. This paper will discuss design trades for such capabilities and present design configurations. The paper will also identify key technologies needed to support the implementation of the new facility.