Although other pre-existing telescopes such as the Nordic Optical Telescope had lightweight mirrors supported by actuators, the NTT is claimed to be the first telescope using full active optics. Its design as well as the design of its enclosure (the building protecting it) included many revolutionary features, from whence it was named. In particular, great care was taken to ensure a good ventilation of the telescope, and to avoid heat sources in around the telescope. Since its construction, the NTT has undergone several upgrades which continued to improve its quality. It was used as a real-life test bench for the engineering concepts and software used for the Very Large Telescope.