  The next generation of solar telescopes will enable us to resolve the
fundamental scales of the solar atmosphere, i.e., the pressure scale height and
the photon mean free path. High-resolution observations of small-scale
structures with sizes down to 50 km require complex post-focus instruments,
which employ adaptive optics (AO) and benefit from advanced image restoration
techniques. The GREGOR Fabry-Perot Interferometer (GFPI) will serve as an
example of such an instrument to illustrate the challenges that are to be
expected in instrumentation and data analysis with the next generation of solar
telescopes.
