Very Large Telescope Interferometer

Tytler D. (1997) Cosmology with the Very Large Telescope Interferometer using a space-based astrometric reference frame. CERN Document Server astro-ph/9701197. 

VLT Very Large Telescope, the combination of four 8m diameter ground-based telescopes and a set of 1.8 m auxiliary telescopes at Paranal Observatory of the European Southern Observatory. The telescopes can be used individually or as an interferometer (VLTI) providing very high spatial resolution. 

To achieve such angular resolution there are two options a very large aperture single dish telescope, or an array of telescopes, this is, an interferometer. It is possible for ground based systems to consist of very large apertures, but for space observatories there are launch requirements that limit both the size and the weight of the telescopes. In order to improve on the existing resolution in space, interferometry is therefore the most plausible solution. 

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