If you had a phased array of high speed photodiodes that were spaced sufficiently far apart, would it be possible to apply beamforming theory to create a steerable visible light "telescope"?
Traditional, earth-bound telescopes are limited by the size of their primary mirror due to the mechanical properties of figured glass as the size increases. Additionally, the larger the primary mirror the more robust the tracking mechanism needs to be to handle the weight.
It seems that if you could instead "virtually" track the object by beamforming the output of a horizontally mounted photodiode array, you are no longer limited by the size of a primary mirror and/or infrastructure to physically move the telescope. Angular resolution could be increased simply by making the array larger. Furthermore, your tracking accuracy is only dependent on your software processing and electronics, not moving parts.
Of course, the problem likely becomes dealing with immense quantity of data collected from the photodiode array, and the sheer physical size of the array.
Light travels at about 299,700 km/s in air, so ~29.97 cm/µs. That seems within the realm of high-speed electronics given a large enough array (10x10m?)
Difficult, huge amount of data...but it doesn't seem impossible unless I'm misunderstanding how beamforming works?