Here is a list of currently existing astronomical optical interferometers (i.e. operating from visible to mid-infrared wavelengths), and some parameters describing their performance.
Higher limiting magnitude means that the array can observe fainter sources.
The limiting magnitude is determined by the atmospheric seeing, the diameters of the telescopes and the light lost in the system.
Columns 6-10 indicate the approximate quality and total amount of science data the array is expected to obtain.
This is per year, to account for the average number of cloud-free nights on which each array is operated.