The status of Japan's planning of the optical/infrared astronomy projects for the 2010's is briefly reviewed. The road map shows a 30 m class extremely large ground based telescope project with advanced adaptive optics capability, JELT, and a mid-infrared optimized 3.5 m space telescope project, SPICA, as the top-priority major project to be accomplished probably on international collaboration basis.

Modelling and simulation, based on observational data, were used to examine the potential of ELT photometry for studies of the evolution of distant galaxies. An open cluster, a globular cluster and two mixed field populations were employed. Colour-magnitude and metallicity diagrams were examined. For younger populations, excellent turn-off-point age data and abundance data can be obtained even beyond 20Mpc. Higher population age weakens data if not improved with longer exposures. Still, the great potential of ELT photometry for studies of the evolution of galaxies is confirmed. Comments are given on adaptive optics and photometry.

The detection of telluric extra-solar planets implies an extremely high contrast long exposure imaging capability at near-infrared and probably visible wavelengths. We present here the core of any Planet Finder instrument which is the extreme AO sub-system. The level of AO correction directly impacts on the exposure time required for planet detection. The extreme adaptive optics system has to correct for the perturbation induced by the atmospheric turbulence as well as for the internal aberrations of the instrument itself. An example of application is proposed in the frame of the EPICS project (XAO system for the ESO OWL telescope).

For a European ELT, we discuss science requirements and technical options. Science includes from the solar system to the first stars and galaxies. ELT and instrument needs are commented. Design options are discussed for the primary mirror, its segmentation and shape, and an adaptive secondary mirror. Adaptive optics and enclosure are commented.