The Vacuum Tower Telescope (VTT) is a solar optical telescope, situated in the Teide Observatory, on Tenerife in the Canary Islands. Along with GREGOR, it is operated by the German consortium of the Leibniz Institute for Solar Physics in Freiburg (KIS), the Leibniz Institute for Astrophysics Potsdam (AIP), and the Max Planck Institute for Solar System Research in Göttingen (MPS). The primary mirror of VTT has a diameter of 0.7 meter and a focal length of 46 meter. A vertical coelostat at the top of the building feeds the light to the primary mirror in the lower the building. The building itself has a height of 38 meter, and its inner tower hosts a vacuum tank that minimizes air turbulence along the optical path, while the outer tower protects the telescope from the strong winds and houses further ancillary utilities.
The Kiepenheuer Institute Adaptive Optics (KAOS) system improves substantially the image quality, leading to sub-arcsec spatial resolution on days with good seeing. The optical laboratory and instrumentation of VTT offer diverse optical instruments offering high spectral, spatial, and temporal resolution. They are tailored towards a wide array of science cases including but not limited to solar oscillations, chromospheric heating, magnetic flux emergence, evolution of active regions.