A new concept for a Very Large Telescope is presented. A filled aperture of about 12 m diameter is realized by a central monolith surrounded by a ring of sectors. It represents a pure two-mirror Ritchey-Chretien optics. The optics is supported by a yoke mount of extreme rigidity. It allows easy access to a very large focal area.
Th . Schmidt-Kaler,
"A New Concept For A Full-Aperture Large Telescope", Proc. SPIE 0628, Advanced Technology Optical Telescopes III, (20 August 1986); doi: 10.1117/12.963534; https://doi.org/10.1117/12.963534